ROSH REVIEW Dermatology
One Step Further Question: Which type of louse is responsible for pubic infestations?
Answer: Pthirus pubis.
A 34-year-old man presents with a purulent skin infection. Which of the following oral antibiotics will cover community-acquired methicillin-resistant Staphylococcus aureus (MRSA)? Amoxicillin Cephalexin Doxycycline Vancomycin
Correct Answer ( C ) Explanation: Methicillin-resistant Staphylococcus aureus (MRSA) is a strain of staphylococcus that has developed resistance to beta-lactam antibiotics. This resistant strain is often healthcare-associated, but is also found in the community. For limited community-acquired infections not requiring hospitalization, patients may be treated with oral antibiotics. A tetracycline (such as doxycycline) is an acceptable choice to treat community-acquired MRSA. Clindamycin or a sulfa drug (such as TMP-SMX) is another acceptable alternative. Healthcare-associated strains of MRSA are typically not susceptible to these oral antibiotics and will require IV vancomycin. Vancomycin is a bacteriostatic drug that inhibits cell-wall biosynthesis.
One Step Further Question: How do you make the definitive diagnosis for Stevens-Johnson syndrome?
Answer: A skin biopsy.
One Step Further Question: The superficial fungal infections are most commonly caused by dermatophytes in what genera?
Answer: Epidermophyton, Trichophyton, and Microsporum genera.
One Step Further Question: What histological finding is typical of molluscum contagiosum lesions?
Answer: Henderson-Paterson bodies.
One Step Further Question: What bacteria has a gram stain showing gram-positive cocci in chains?
Answer: Streptococcus.
One Step Further Question: What are the TORCH infections associated with severe birth defects?
Answer: Toxoplasmosis, "others" (including syphilis, varicella zoster, and parvovirus B19), rubella, cytomegalovirus, and herpes simplex virus.
One Step Further Question: What type of hypersensitivity reaction is allergic contact dermatitis?
Answer: Allergic contact dermatitis is a form of delayed hypersensitivity (type IV) reaction mediated by lymphocytes sensitized by the contact of the allergen with the skin.
One Step Further Question: What medications may be used in the treatment of patients with hidradenitis suppurativa?
Answer: Antibiotics, retinoids, corticosteroids, anti-androgenic agents, estrogen derivatives, immunosuppresants and 5-alpha-reductase inhibitors have all been described for use in the treatment of hidradenitis suppurativa
One Step Further Question: For non-crusted scabies, how should permethrin cream be applied?
Answer: Apply all over body overnight once and reapply in 14 days if mites are still present.
One Step Further Question: When should treatment be initiated in pregnancy to prevent neonatal infection?
Answer: Around 32 weeks gestation
One Step Further Question: What is the ABCDE rule when used to evaluate for malignant melanoma?
Answer: Asymmetry, border (irregular), color (not uniform), diameter (> 6 mm), elevation or enlarging rapidly.
One Step Further Question: What common neuromuscular blockade can be used to treat severe lichen simplex chronicus?
Answer: Botulism toxin injections.
One Step Further Question: What is the most common autoimmune blistering disease in the elderly?
Answer: Bullous pemphigoid.
One Step Further Question: How are brown recluse spiders identified?
Answer: By the violin-shaped pattern on the cephalothorax.
One Step Further Question: For what indication is oral vancomycin most useful?
Answer: C. difficile colitis.
One Step Further Question: What is the only topical prescription medication available in the United States for the treatment of onychomycosis?
Answer: Ciclopirox 8% solution.
One Step Further Question: What is the pathognomonic description of the scale of pityriasis rosea?
Answer: Cigarette paper.
One Step Further Question: What syndrome can result from circumferential eschar from a full-thickness burn?
Answer: Compartment syndrome.
One Step Further Question: What is the name given to wart-like genital lesions associated with secondary syphilis?
Answer: Condyloma lata.
One Step Further Question: What is the causative organism of hand-foot-and-mouth disease?
Answer: Coxsackie virus.
One Step Further Question: What is the prognostic indicator of a melanoma lesion?
Answer: Depth of invasion.
One Step Further Question: What is the most common etiology of onychomycosis?
Answer: Dermatophyte infection.
One Step Further Question: What office tool can be used to aid in the visualization of Wickham's striae?
Answer: Dermatoscope.
One Step Further Question: What is the appropriate treatment for Iatrogenic Immunosuppression-Associated Kaposi sarcoma?
Answer: Discontinue immunosuppressive medications.
One Step Further Question: What is the ulcerative form of impetigo called that extends into the deep dermis?
Answer: Ecthyma.
One Step Further Question: What are the most common species of dermatophytes?
Answer: Epidermophyton, trichophyton, and microsporum.
One Step Further Question: Which two HPV strains are commonly associated with cervical cancer and are therefore targeted in HPV vaccines?
Answer: HPV types 16 and 18.
One Step Further Question: What is the most common serious side effect of treatment with oral ketoconazole?
Answer: Hepatic toxicity
One Step Further Question: What is the name of the initial lesion seen in pityriasis rosea?
Answer: Herald patch.
One Step Further Question: What is the commonly implicated etiologic agents of pityriasis rosea?
Answer: Human herpesviruses 6 and 7.
One Step Further Question: What staging system is used in the diagnosis of hidradenitis suppurativa?
Answer: Hurley staging system.
One Step Further Question: What is the lethal disease that results from the parvovirus in pregnancy?
Answer: Hydrops fetalis.
One Step Further Question: Which pharmacological treatment was recently approved by the FDA for treatment of inflammatory lesions of rosacea.
Answer: Ivermectin topical cream was approved by the FDA in December 2014.
One Step Further Question: What dermatologic sign can erythema multiforme display?
Answer: Koebner sign.
One Step Further Question: What is the medical term for the manifestations of widow spider bites?
Answer: Latrodectism.
One Step Further Question: Is the zoster vaccine a live attenuated or inactivated vaccine?
Answer: Live attenuated.
One Step Further Question: What are the unique laboratory findings of pleural effusions associated with rheumatoid arthritis?
Answer: Low glucose, low pH and high LDH.
One Step Further Question: What dermatophyte causes tinea versicolor?
Answer: Malasezzia species such as M. globosa and M.furfur.
One Step Further Question: What treatment can be given for prophylaxis against repeat episodes of tinea versicolor?
Answer: Monthly application of propylene glycol, selenium shampoo or azole creams can be used for prophylaxis
One Step Further Question: What is another name for procaine?
Answer: Novocain, a common local anesthetic used by dentists—and an ester.
One Step Further Question: What are 3 predisposing factors for intertrigo?
Answer: Obesity, diabetes mellitus and HIV.
One Step Further Question: What complication should herpes zoster lesions at the tip of the nose alert the clinician to?
Answer: Ocular herpes zoster is correlated with lesions at the tip of the nose - called Hutchinson's sign.
One Step Further Question: How soon after removal of an infected pacemaker can another permanent pacemaker be placed?
Answer: Only after 4-6 weeks of intravenous antibiotics.
Question: What are the redundant skin folds at the corners of the mouth that predispose the elderly for candidal intertrigo called?
Answer: Perlèche.
One Step Further Question: What is the first line medication for the treatment of scabies?
Answer: Permethrin 5% cream.
One Step Further Question: How frequently should a patient with scabies use topical permethrin?
Answer: Permethrin will not kill unhatched mites so they must apply it twice, one to two weeks apart.
One Step Further Question: Which rosacea subtype is more common in men than women?
Answer: Phymatous rosacea.
One Step Further Question: What is an adjunctive treatment to isotretinoin in treating severe or resistant acne vulgaris?
Answer: Prednisone.
One Step Further Question: Bacterial colonization of which species is associated with acne vulgaris?
Answer: Propionibacterium acnes.
One Step Further Question: What labs should be considered in pityriasis rosea?
Answer: RPR or VDRL to rule out syphilis.
One Step Further Question: What other tick-borne disease presents as a faint maculopapular rash that begins on the wrists and ankles and spreads to the extremities and trunk?
Answer: Rocky Mountain spotted fever (Rickettsia rickettsi)
One Step Further Question: What distinguishes Stevens-Johnson Syndrome from toxic epidermal necrolysis?
Answer: SJS involves less than 10 % BSA epidermal detachment whereas TEN has epidermal detachment in greater than 30% BSA.
One Step Further Question: What kind of agar is used to grow dermatophytes in culture?
Answer: Sabouraud's agar.
One Step Further Question: What is the name of the obligate human parasite that causes scabies?
Answer: Sarcoptes scabiei.
One Step Further Question: What is the most common complication of atopic dermatitis?
Answer: Secondary bacterial infections due to frequent disruption of the skin barrier.
One Step Further Question: What treatment should be given to colonized household contacts of children with tinea capitis?
Answer: Selenium sulfide shampoo.
One Step Further Question: What are first-line treatments for melasma?
Answer: Skin-lightening agents and retinoids.
One Step Further Question: Human papillomavirus is a risk factor for the development of what skin malignancy?
Answer: Squamous cell carcinoma.
One Step Further Question: What is black dot Tinea capitis?
Answer: This refers to an infection that causes the hair to fracture, leaving the infected dark stubs visible in the infected regions.
One Step Further Question: What is the most common location for zoster to occur in?
Answer: Thorax, followed by the face (trigeminal nerve)
One Step Further Question: What is the treatment for herpes simplex?
Answer: Three medications can be used for treatment of herpes infections: acyclovir, valacyclovir, and famciclovir.
One Step Further Question: Other than celiac disease, what is the most common autoimmune disorder associated with dermatitis herpetiformis?
Answer: Thyroid disease.
One Step Further Question: What is a dermatophyte infection on the hands called?
Answer: Tinea manuum.
One Step Further Question: Besides Tinea capitis, which other tinea infection should be treated with systemic antifungal medication?
Answer: Tinea unguium (onychomycosis).
One Step Further Question: What term solely refers to dermatophyte nail infections?
Answer: Tinea unguium.
A 19-year-old woman presents to her primary care provider's office for a rash on the back of her neck that has grown and gotten darker over the past year. The woman has a past medical history asthma. Her pulse is 66 beats/min, respiratory rate is 18 breaths/min, blood pressure is 132/87 mm Hg, and her body mass index is 29. On exam, there is a horizontal, dark, velvety plaque on her posterior neck. Which of the following diagnostic studies is most appropriate? Fasting blood glucose level Punch biopsy of the plaque Serum antinuclear antibody level Serum cholesterol level
Correct Answer ( A ) Explanation: A fasting blood glucose level should be obtained to evaluate for diabetes mellitus, which is frequently associated with acanthosis nigricans. Acanthosis nigricans is a common skin condition that is characterized by velvety, hyperpigmented plaques. Acanthosis nigricans recognition is important because of its association with several systemic diseases. Obesity, insulin resistance, and diabetes mellitus are the most commonly associated disorders. Internal malignancy may rarely cause acanthosis nigricans. Acanthosis nigricans is more common in Native Americans, African Americans, and Hispanics than in Caucasians or Asians. Hyperinsulinemia is thought to play a major role in the development of the hyperpigmented plaques by stimulating keratinocyte proliferation. Acanthosis nigricans typically presents as a thick, brown, horizontal plaque on the back of the neck or axillae. Early plaques have a dirty appearance that may become thicker and darker as the disease progresses. Acanthosis nigricans typically has a symmetrical distribution. Patients with acanthosis nigricans should under go evaluation for associated diseases like type 2 diabetes mellitus, polycystic ovarian syndrome, and metabolic syndrome. Diagnostic studies may include fasting blood glucose, hemoglobin A1C, and postprandial blood glucose.
A 32-year-old man reports a history of developing diffuse urticaria after taking amoxicillin. To which of the following antibiotics is he most likely to have an allergy? Cefazolin Cefepime Cefoxitin Ceftriaxone
Correct Answer ( A ) Explanation: Amoxicillin is an antibiotic in the penicillin family. Allergic reactions to penicillin are the most commonly reported medication allergy. It is important to understand the actual symptoms of the reported allergy as studies have shown that up to 90% of patients with a "history" of a penicillin allergy do not have a true allergy. True anaphylaxis occurs less than 0.01% of the time. All of the answer choices are cephalosporin antibiotics. Cephalosporins share a similar β-lactam ring structure to penicillins and rates of cross-reactivity between the two classes of medication are reportedly between 1% and 8%. However, this risk appears to be significantly more with first generation cephalosporins like cefazolin. Additionally, the risk for allergy to cephalosporins is also more likely in patients who had a severe reaction to penicillin
A 60-year-old white woman presents to clinic with concerns of a spot on her forearm that she noticed about six months ago. It has not changed during this time, but she is concerned as she has a long personal history of using tanning beds. On physical examination, you notice a small flesh-colored nodule with a pearly border. What is the most likely diagnosis? Basal cell carcinoma Kaposi sarcoma Malignant melanoma Squamous cell carcinoma
Correct Answer ( A ) Explanation: Basal cell carcinoma is the most common form of skin cancer, usually affecting fair-skinned individuals with a history of cumulative sun exposure, such as this patient. Treatment is often surgical, and Mohs micrographic surgery is now preferred for lesions with a high risk of recurrence. The event of improved surgical techniques and the low rate of metastatic disease makes for a favorable prognosis. Regardless, it is necessary to biopsy any suspicious lesion to ensure the diagnosis of basal cell carcinoma. These lesions will present as pink or flesh-colored nodules with a pearly or translucent quality. A classic description is that these lesions have a pearly or a rolled border, as in this patient's case.
Which of the following conditions is associated with celiac disease? Dermatitis herpetiformis Erythema marginatum Pemphigus vulgaris Stevens-Johnson syndrome
Correct Answer ( A ) Explanation: Dermatitis herpetiformis is a dermatologic condition associated with celiac disease. It is an uncommon autoimmune, cutaneous eruption that occurs as a manifestation of gluten sensitivity. Affected patients typically develop intensely pruritic inflammatory papules and vesicles on the forearms, knees, scalp, or buttocks. Genetic predisposition and gluten-sensitivity are key factors in the pathogenesis and virtually all patients carry the HLA DQ2 or HLA DQ8 haplotype. Antibodies against epidermal transglutaminase produced in association with an immune response to ingested gluten play a key role in the disease pathogenesis. Dapsone and a gluten-free diet are the primary interventions for the management of this disease. Dermatitis herpetiformis is usually a life-long condition that requires continued treatment. Erythema marginatum (B) is an evanescent, pink or faintly red, non-pruritic rash involving the trunk and sometimes the limbs that is associated with acute rheumatic fever. Pemphigus vulgaris (C) is an autoimmune disorder characterized by autoantibodies to adhesion molecules in the epidermis which cause bullae to develop, which rupture and lead to widespread erosions and desquamation. Stevens-Johnson syndrome (D) is a severe mucocutaneous reaction characterized by extensive necrosis and detachment of the epidermis. This is a rare but serious side effect of certain medications and requires hospitalization.
A 66-year-old white man who recently immigrated from the Czech Republic presents to clinic complaining of a "rash" on his feet. Initially, he believed it was a bruise. It has not gone away since he first noticed it over a month ago. Physical exam reveals multiple purple-brownish plaques on the lateral sides of both of his feet. What is his most likely diagnosis? Kaposi sarcoma Nodular vasculitis Polyarteritis nodosa Reactive arthritis
Correct Answer ( A ) Explanation: Kaposi sarcoma (KS) is a systemic tumor that requires a co-infection with human herpesvirus 8. The cells arise from the endothelium of the blood or lymphatic microvasculature, leading to mucocutaneous lesions. A skin biopsy establishes diagnosis, and treatment often includes radiotherapy for limited disease or chemotherapy for more aggressive disease. Prognosis often depends on the extent of the disease, and the specific variant, but survival may be anywhere from five to fifteen years. There are four different variants - Classic or European KS, African-Endemic KS, Iatrogenic Immunosuppression-Associated KS, and HIV/AIDS-Associated KS. As indicated by their names, European KS is more common in Eastern-Europeans, while African-Endemic KS is often seen in the area in and around Zaire. While each variant is more common in certain populations, they all present with characteristic skin lesions that often start as ecchymotic-like macules that are often mistaken for bruises. These macules then evolve into red, pink or tan plaques, and eventually into purple-brownish tumors that may spread and cause lymphedema. The clinical picture of an elderly man of Eastern-European heritage with purple-brownish lesions on his feet is most consistent with classic KS. Nodular vasculitis (B) is a form of panniculitis that leads to lipocyte injury, necrosis, inflammation, and granulation. It often presents as bluish nodules on the posterior aspect of the lower legs, not as purplish plaques as seen in this patient. Polyarteritis nodosa (C) is a necrotizing vasculitis that often presents as palpable purpura, nodules, and ulcers on the pretibial aspect of the lower legs which does not fit the clinical features of this patient.
Which of the following statements is true regarding the condition seen above? Leads to scarring alopecia Primarily due to bacterial infection Requires long-term topical treatment with antifungal Usually painless
Correct Answer ( A ) Explanation: The image depicts a patient with a kerion. This condition begins as Tinea capitis (scalp ringworm) that undergoes a delayed-type hypersensitivity reaction to the causative fungus. This inflammation causes the initial erythematous, scaly plaque of Tinea capitis to become boggy with inflamed purulent nodules and plaques. The hair follicle is frequently destroyed by the inflammatory process in a kerion, leading to scarring alopecia. Treatment includes long-term systemic therapy, usually with oral griseofulvin and the addition of an antibiotic to treat any secondary bacterial infection. In addition, oral corticosteroids are administered to treat the severe inflammation.
A 27-year-old man presents with painful, swelling of his fingertip for three days as shown above. He also reports subjective fever and malaise. Which of the following represents the best course of management? Analgesia and a clean dressing Bedside incision and drainage Intravenous antibiotic administration and hospital admission Operative open irrigation and debridement
Correct Answer ( A ) Explanation: The patient has herpetic whitlow. This is a localized infection caused by the herpes simplex virus. Inoculation most commonly occurs when the patient touches herpetic lesions on the mouth or genitals. Physical examination reveals grouped vesicles on an erythematous base. Analgesia and a clean dressing minimizes the chance of transmission to other people or other areas of the body. Topical acyclovir may decrease the length of illness and oral acyclovir may decrease the risk of recurrence, but this is controversial.
A 29-year-old woman presents to the ED with concerns regarding a "spot" on her arm that seems to have grown rapidly over the course of the last 2-3 months. The lesion is shown above. Which of the following is the most important prognostic factor in staging this lesion? Depth of the lesion Diameter of the lesion Lymph node involvement Pigment of the lesion
Correct Answer ( A ) Explanation: This patient has history and exam findings consistent with malignant melanoma, a highly aggressive malignancy of the pigment-producing cells (melanocytes) of the skin. This is the least common form of skin cancer; however, it holds the highest mortality. Risk factors include fair skin, sun exposure, and family history. It may arise de novo (70%) or from dysplastic nevi (30%). The most important prognostic factor for staging this malignancy is the depth of the lesion on biopsy. Signs and symptoms include new or changes to an existing mole and the ABCDE rule is used for diagnosis. The ABCDE rule consists of asymmetry of the lesion, border (irregular), color (not uniform), diameter (> 6 mm), and elevation or enlarging rapidly. The presence of these elements should raise your suspicion substantially for malignant melanoma. Formal diagnosis is made on skin biopsy. Management is surgical excision with wide margins. Early detection and excision is key and often curative. There is a much poorer prognosis with metastasis and lymph node involvement. Chemotherapy may be used for metastatic disease but has no effect on overall survival.
A 16-year-old man presents with a rash to the back for 1 week. He states that the rash started as a single patch and then spread to the rest of his back. The rash is itchy but otherwise, the patient is asymptomatic. What management is indicated? Antihistamines Cephalexin Oral corticosteroids Topical antifungals
Correct Answer ( A ) Explanation: This patient presents with pityriasis rosea and should be treated symptomatically with antihistamines as the condition is self-limiting. Pityriasis rosea presents as scaly, salmon colored, oval papules or plaques 1 - 2 cm in diameter on the trunk and proximal extremities. It usually presents in children and young adults. Classically, the diffuse rash is preceded by a herald patch 1 week prior. This lesion is larger (2-5 cm in diameter) than the others that form. Patients may also initially have fever, malaise or lymphadenopathy prior to the appearance of a rash but this is rare. The diffuse form of the rash has a Christmas tree-like distribution following the cleavage lines of the skin. Pityriasis rosea is a self-limiting disease but may take 8-12 weeks to completely resolve. The causative agent is unknown although a virus is suspected (HHV 7). There is no specific treatment for the disease and so care should be directed at relieving symptoms, most commonly itching, with antihistamines.
A patient presents to the emergency department with severe burns from a gas explosion. The burn appears waxy dry and red with blistering. It does not blanch with pressure and is only painful to pressure. Which of the following is the most accurate classification of burn in this patient? Deep partial-thickness burn Full-thickness burn Superficial burn Superficial partial-thickness burn
Correct Answer ( A ) Explanation: This patient's presentation is most consistent with a deep partial-thickness burn. Current designations of burn depth are superficial, superficial partial-thickness, deep partial-thickness, and full-thickness. The term fourth degree is still used to describe the most severe burns, burns that extend into the muscle, bone, or joints. Superficial burns involve only the epidermal layer of skin. They do not blister but are painful, dry, red, and blanch with pressure. This process is commonly seen with sunburns. Partial thickness burns involve the epidermis and portions of the dermis. They are characterized as either superficial or deep. Superficial partial-thickness burns characteristically form blisters and are painful, red, and weeping, and blanch with pressure. Deep partial-thickness burns extend into the deeper dermis and damage hair follicles and glandular tissue. They are painful to pressure only, almost always blister, are wet or waxy dry, and have variable mottled colorization from patchy cheesy white to red. They do not blanch with pressure. These burns invariably cause hypertrophic scarring. Full-thickness burns extend through and destroy all layers of the dermis and often injure the underlying subcutaneous tissue. Burn eschar, the dead and denatured dermis, is usually intact. The eschar can compromise the viability of a limb or torso if circumferential. Full thickness burns are usually anesthetic or hypoesthetic. Skin appearance can vary from waxy white to leathery gray to charred and black. The skin is dry and inelastic and does not blanch with pressure. Vesicles and blisters do not develop.
Which one of the following Tinea infections in children always requires systemic antifungal therapy? Tinea capitis Tinea corporis Tinea cruris Tinea pedis
Correct Answer ( A ) Explanation: Tinea infections are caused by dermatophytes and are classified by the involved site. The most common infections in prepubertal children are tinea corporis and tinea capitis, whereas adolescents and adults are more likely to develop tinea cruris, tinea pedis, and tinea unguium (onychomycosis). In the United States, tinea capitis (scalp) most commonly affects children of African heritage between three and nine years of age. Early disease can be limited to itching and scaling, but the more classic presentation involves scaly patches of alopecia with hairs broken at the skin line and crusting. Tinea capitis may progress to kerion, which is characterized by boggy tender plaques and pustules. Tinea capitis must be treated with systemic antifungal agents because topical agents do not penetrate the hair shaft. However, adjunct treatment with selenium sulfide shampoo or 2% ketoconazole shampoo should be used for the first two weeks because it may reduce transmission. For many years, the first-line treatment for Tinea capitis was griseofulvin because it has a long track record of safety and effectiveness. However, randomized clinical trials have confirmed that newer agents, such as terbinafine and fluconazole, have equal effectiveness and safety and shorter treatment course.
In which of the following patients is a zoster vaccination indicated? A 26-year-old pregnant woman A 61-year-old man who recalls having chicken pox as a child A 7-year-old boy with asthma A 75-year-old woman with chronic lymphocytic leukemia
Correct Answer ( B ) Explanation: A zoster vaccine is indicated in a 61-year-old man who recalls having chicken pox as a child. The CDC recommends the zoster vaccine for use in people 50-years-old and older to prevent shingles. This is a one-time vaccination. Anyone 50-years of age or older should get the shingles vaccine, regardless of whether they recall having had chickenpox or not. Varicella-zoster virus infection causes two clinically distinct forms of disease. Primary infection with varicella-zoster virus results in varicella, characterized by vesicular lesions in different stages of development on the face, trunk and extremities. Herpes zoster is related to reactivation of varicella-zoster virus infection and is characterized by a painful, unilateral vesicular eruption in a restricted dermatomal distribution. Individuals who have not had varicella and are exposed to a patient with herpes zoster are at risk for developing primary varicella and not herpes zoster. Vaccination reduces the risk of zoster and postherpetic neuralgia.
A 19-year-old Hispanic man with a body mass index of 32 kg/m2 presents to your office with a complaint of darkened skin. Physical exam reveals thickened, velvety, darkly pigmented plaques on the back of his neck. Which of the following is the most appropriate next step in management? Referral to gastroenterology Screening for diabetes mellitus Skin biopsy Trial of topical retinoids
Correct Answer ( B ) Explanation: Acanthosis nigricans is a dermatologic condition characterized by darkened plaques, most commonly in the intertriginous sites such as the axillae or neck. A significant percentage of patients who are obese or have diabetes have this condition, and the presence of acanthosis nigricans in children is a risk factor for the development of diabetes. Ethnic differences are seen with a higher percentage of African-American and Hispanic patients having the condition than non-Hispanic whites or Asians. Rarely, acanthosis nigricans can develop as a result of malignancy. Diagnosis is by clinical examination and assessment for other disorders, including screening for diabetes mellitus, is an important next step in the evaluation of patients with this condition. Acanthosis nigricans is a benign condition and treatment is often based on cosmetic concerns. Treatment of the underlying condition is the preferred method of management.
A five-month-old boy presents to your ED with a rash. He has always had dry skin but the parents note that this rash seems worse. He has had no fevers but has been scratching his face. There is a strong family history of asthma and allergies. He is well appearing on exam with normal vital signs for his age. The blanching rash is located over his face, neck, and extensor surfaces. His diaper area is relatively spared. Which of the following is the most likely diagnosis? Asteatotic eczema Atopic dermatitis Contact dermatitis Dyshidrotic eczema
Correct Answer ( B ) Explanation: Atopic dermatitis is a common chronic remitting disorder of dry skin that frequently frustrates parents and patients and is sometimes referred to as "the itch that rashes." It begins early in life between birth and six months of age and is characterized by papules and plaques that are erythematous and pruritic with occasional oozing, weeping, and crusting. It is often symmetrical in nature. There are three distinct phases that involve different locations despite a similar appearance of the lesions. In the infantile phase, lesions are found on the cheeks, forehead, trunk, and extensor surfaces. In the childhood phase (four to twelve years), lesions are found on the wrists, ankles, antecubital, and popliteal fossa. In the adult phase (> 12 years), lesions are mostly in flexural areas of the arms, neck, and legs, occasionally with lichenification. Treatment is frequent use of topical emollients and topical corticosteroids. Asteatotic eczema (A) is a form of dry skin that also appears as cracked skin with red fissures and scale and is usually seen in adolescents during the winter.
A 28-year-old woman presents to your office with a long history of acne and she is desperate for the correct treatment. She has suffered from acne her entire life and nothing has seemed to work. Her past treatments include benzoyl peroxide, topical tretinoin, and oral and topical antibiotics, yet there was no improvement. She has no significant past medical history. Her physical examination is within normal limits with the exception of prominent scarring and nodulocystic acne. You begin her on the most appropriate treatment for this clinical scenario. Regarding this medication, which of the following is true? Patients should have a pregnancy test after starting the medication Prior to starting the medication, the patient must agree to use two forms of contraception The medication is associated with development of bipolar disorder The medication is indicated as a first-line approach for comedones
Correct Answer ( B ) Explanation: Acne is a chronic inflammatory skin disease that is the most common skin disorder in the United States. Therapy targets the four factors responsible for lesion formation: increased sebum production, hyperkeratinization, colonization by Propionibacterium acnes, and the resultant inflammatory reaction. Oral isotretinoin is appropriate treatment for patients with moderate to severe acne that is predominantly nodulocystic and resulting in scars. However, it is also a potent teratogen. Patients must agree to pregnancy tests before and during use as well as two lines of contraception. Other side effects are elevated cholesterol, triglycerides, LFTs, as well as depression, joint pain, and skin dryness. Recall the other treatments for acne. Benzoyl peroxide is a useful first line approach for comedones. Topical tretinoin can be used with benzoyl peroxide in severe cases. Topical antibiotics (erythromycin or clindamycin) are useful for inflammatory cysts and may also be given systemically. Controversies associated with isotretinoin therapy for acne include the risk of depression or suicide, inflammatory bowel disease, and the iPledge program. A small amount of patients experience depression which stops after the drug is discontinued. Despite the iPledge program, a small number of women still become pregnant on the drug.
A 65-year-old woman presents with skin lesions seen above. When you apply lateral pressure to the bullae, they do not extend. Which of the following statements is correct regarding this condition? Bullae evolve into painful ulcers It is a chronic autoimmune disease Often seen in young individuals Oral lesions are present in a majority of cases
Correct Answer ( B ) Explanation: Bullous pemphigoid is a chronic autoimmune blistering disease often seen in patients older than 60 years of age. The blisters occur deep, within the epidermal basement membrane, which is why they do not extend with lateral pressure (Nikolsky sign negative). The Nikolsky sign is dislodgement of intact superficial epidermis by a shearing force, indicating a plane of cleavage in the skin. The defect may be due to staphylococcal toxin as in staph-scalded skin syndrome, or to epidermal antibodies as in pemphigus.The bullae evolve over weeks to months and most commonly occur in the axillae, abdomen, inner thighs, flexural forearms, and lower legs. The affected skin may be intensely pruritic. Pemphigus vulgaris (A and D) is associated with bullous lesions that often occur in the perioral region and erode to leave painful ulcers. Pemphigus vulgaris is associated with a positive Nikolsky sign. Bullous pemphigoid occurs mainly in individuals older (C) than 60 years of age. Pemphigus vulgaris occurs most commonly in younger individuals aged 40 to 60 years.
A 25-year-old man presents to your office after having noticed a slightly raised red lesion with central clearing that increased in size over the past five days. He describes feeling flu-like symptoms and states that he had been camping in Connecticut recently. Based on the clinical presentation, which of the following is the best treatment option for this patient? Ceftriaxone 250 mg single dose intramuscular injection Doxycycline 100 mg oral tablet twice per day for 21 days Metronidazole 2 g single dose tablet orally Watch and wait
Correct Answer ( B ) Explanation: Doxycycline 100 mg oral tablet twice per day for twenty-one days is the correct treatment and dosing for the suspected diagnosis of Lyme disease with a known erythema migrans (bulls-eye) rash. Lyme disease is caused by the spirochete Borrielia burgdorferi. It is transmitted to humans through a tick bite. The disease is most common in the northeastern United States, with Connecticut having one of the highest prevalence rates. It is recommended to treat any patient with suspected Lyme disease with an associated erythema migrans rash
A 22-year-old man presents to the emergency department after being bitten by a shiny, black spider. He complains of severe abdominal pain and cramping. On exam, there is intermittent muscle rigidity involving his right arm, abdomen, and back. There is a pale circular patch around a central punctum and surrounding erythema on the posterior surface of his right hand. Which of the following is the most appropriate treatment? Black widow antivenin Intravenous morphine and diazepam Intravenous sodium bicarbonate Oral cephalexin and wound debridement
Correct Answer ( B ) Explanation: Intravenous morphine and diazepam is the most appropriate treatment for this man with moderate widow spider envenomation. In the United States, widow spiders (genus Latrodectus) are one of the most commonly implicated species in envenomations. Black widow spiders are commonly encountered outdoors in cluttered areas, such as garages, wood piles, or sheds. People are commonly bitten while putting on shoes or gloves, gathering or chopping wood, or moving garbage. The majority of bites are on the extremities. The black widow venom is an excitatory neurotoxin that triggers large exocytosis from presynaptic nerve terminals. Patients typically present acutely with pain around the bite and severe abdominal pain. Vital signs are usually within normal limits. Intermittent muscle rigidity adjacent to the bite or involving the abdomen, chest, or back is present in more than half of patients. The bite appears as a circular area of pallor with a surrounding erythematous perimeter and a central puncture. Laboratory studies are unnecessary and are non-specific. Additional diagnostic imaging may be required to rule out abdominal surgical emergencies that can also cause severe abdominal pain and rigidity. Patients with mild envenomation can be managed with local wound care, oral analgesics, and tetanus prophylaxis. Moderate to severe envenomation treatment involves wound care, tetanus prophylaxis, parenteral opioids, and parenteral benzodiazepines. Intravenous calcium is not generally recommended. Widow antivenom is recommended for patients with severe envenomation that are unresponsive to parenteral analgesic and benzodiazepine therapy. Most patients with widow spider bites can be managed on an outpatient basis. Pain typically resolves within 24-72 hours if untreated. Black widow antivenin (A) is not yet indicated in this patient. Antivenin is reserved for patients unresponsive to opioids and benzodiazepines. Indications for antivenom include severe and persistent pain and muscle cramping, hypertension and tachycardia, or difficulty breathing. Black widow antivenom has the potential to cause anaphylaxis and is a pregnancy class C. Asthma and allergy to horses are relative contraindications.
Which of the following is most suggestive of measles infection? A prodrome of fever, lymphadenopathy, and conjunctivitis followed by a maculopapular rash that starts on the face and spreads to the trunk and limbs Diffuse maculopapular rash with white spots on the buccal mucosa High fever for 3 days followed by the appearance of a pink maculopapular rash after defervescence Presence of shallow ulcers on oral mucosa and vesicular lesions on the palms and soles
Correct Answer ( B ) Explanation: Measles (rubeola) is caused by a paramyxovirus and spread by respiratory contact. Measles begins with a prodrome of fever, coryza, cough, and conjunctivitis for several days followed by the development of a morbilliform rash. The rash starts with erythematous maculopapular lesions a few millimeters in diameter which become confluent. The rash typically starts on the face and spreads to the extremities. White spots on the buccal mucosa, known as Koplik spots, are pathognomonic for measles. Complications include otitis media, pneumonia, myocarditis, pericarditis, and encephalitis. Treatment is supportive.
A 29-year old man presents with complaints of deformed and discolored toenails. On exam, you note the findings seen above. A KOH scraping from the subungual debris is positive for hyphae. Which of the following is the most appropriate first-line treatment for this patient? Oral ketoconazole 200 mg daily for 6 weeks Oral terbinafine daily for 12 weeks Oral trimethoprim/sulfamethoxazole daily for 12 weeks Topical ketoconazole daily for 6 weeks
Correct Answer ( B ) Explanation: Onychomycosis describes nail infections caused by any fungus, including dermatophytes, yeasts, and nondermatophyte molds. Onychomycosis may involve the nail plate and other parts of the nail unit including the nail matrix. The majority of distal and proximal subungual onychomycosis results from Trichophyton rubrum. Yeast onychomycosis is most common in the fingers and is most often caused by Candida albicans. The diagnosis is usually clinical but can be confirmed by KOH and culture. Clippings of the nail plate and scrapings of the subungual keratosis can be examined with KOH and microscopy. Nail clippings can also be sent to pathology in formalin to be examined with periodic acid-Schiff (PAS) stain for fungal elements. The first-line treatment is terbinafine, a synthetic antifungal that inhibits ergosterol synthesis. The most concerning side effect of terbinafine is liver failure. Therefore, patients should undergo monitoring of LFTs. A second-line agent is itraconazole.
A previously healthy 65-year-old woman presents to your office with a complaint of thickened and discolored toenails. Previous potassium hydroxide examination of her toenail scrapings shows the presence of dermatophytes. Which of the following is the most appropriate therapy? Oral fluconazole Oral terbinafine Topical medicated chest rub Topical terbinafine
Correct Answer ( B ) Explanation: Onychomycosis is a fungal infection that can affect the toenails or fingernails. There are five different subtypes of onychomycosis that are determined based on clinical features. Patients may present with a combination of these subtypes. Risk factors for onychomycosis include older age, diabetes mellitus, tinea pedis, genetic predisposition, and living with individuals who have onychomycosis. Patients initially present with complaints about the appearance of the nail without physical symptoms. With progression of the infection, thickening, discoloration and deformation of the nails occur and can lead to physical discomfort and pain. Diagnosis is with potassium hydroxide (KOH) examination of nail scrapings. Treatment is indicated for patients with diabetes, with a history of cellulitis, those experiencing pain or physical discomfort and when requested due to cosmetic concerns. First-line treatment is with oral medication. Patients should be advised that recurrence is common. Terbinafine has been found to have the highest cure rate and is taken for six weeks when treating fingernails, twelve weeks when treating toenails. Serum aminotransferases should be monitored before starting treatment with terbinafine and during the treatment process due to hepatotoxicity.
Which of the following patients should be started on isoniazid therapy? 21-year-old woman with a 5 mm PPD reaction and a history of IV drug abuse 40-year-old homeless man with a 10 mm PPD reaction 51-year-old doctor with a 5 mm PPD reaction 8-year-old boy with an 8 mm PPD reaction
Correct Answer ( B ) Explanation: Patients who are medically underserved (homeless, correctional institution residents) should be treated with isoniazid (INH) if their PPD reaction is >10 mm. The tuberculin skin test or PPD is the best tool available for detection of latent tuberculosis (TB). The antigens present in the PPD induce a reaction in patients with latent TB. After placement of the antigen, the patient has the reaction interpreted by a healthcare provider at 48-72 hours. Treatment of latent TB is guided by the reaction as well as patient characteristics as seen in the table below:
A 18-year-old woman presents with a diffuse papulosquamous rash. The rash began one month prior when she noticed a large patch on her neck that was followed by the diffuse papulosquamous rash. You inform the patient that the rash will last 5-8 weeks and prescribe her cetirizine. Which of the following is the most likely diagnosis? Contact dermatitis Pityriasis rosea Scabies Tinea versicolor
Correct Answer ( B ) Explanation: Pityriasis rosea is a common acute eruption usually affecting children and young adults; the cause is unknown. It is characterized by the formation of an initial herald patch, followed by the development of a diffuse papulosquamous rash. Pityriasis rosea is difficult to identify until the appearance of characteristic, smaller, secondary lesions that follow Langer's lines. The rash of pityriasis rosea typically lasts 8 to 12 weeks, with complete resolution in most patients. An important goal of treatment is to control pruritus, which may be severe; zinc oxide, calamine lotion, topical steroids, and oral antihistamines are usually helpful. Systemic steroids are generally not recommended. Patients should be reassured about the self-limited nature of pityriasis rosea. Persistence of the rash or pruritus beyond 12 weeks should prompt reconsideration of the original diagnosis, consideration of biopsy to confirm the diagnosis, and questioning the patient again about use of medications that may cause a rash similar to that of pityriasis rosea.
A 16-year-old boy presents with three days of fever, myalgias, and rash. His rash consists of brownish-red macules and papules scattered over his distal extremities, including his palms and soles. Cervical, axillary, and inguinal lymphadenopathy are also noted on exam. Which of the following is true? ADoxycycline is the treatment of choice BThe rash is a result of a sexually transmitted infection CThe rash is not contagious DThe symptoms require treatment for resolution
Correct Answer ( B ) Explanation: The adolescent presents with symptoms and signs of secondary syphilis. Syphilis is caused by Treponema pallidum and is a sexually transmitted infection. Primary infection begins with the appearance of a painless chancre, typically on the genital region. Because it is painless, the chancre may not come to the individual's attention or to medical attention. The chancre self-resolves within a few weeks. Weeks to months later, about 25 percent of infected individuals will develop secondary syphilis. Secondary syphilis produces a wide variety of symptoms, including a rash, fever, headache, malaise, anorexia, and lymphadenopathy. The rash is the most characteristic feature and can display a wide variety of appearances, including papules, macules, plaques, and pustules. The only type of lesion that is uncommon is vesicles. The lesions are classically brown, red, or copper-colored. Occasionally, mucous membranes and the perineum may display condyloma lata, which are flat, greyish plaques. The scalp may also be involved and display patchy, "moth-eaten" alopecia. The liver, kidneys, eyes, and musculoskeletal system may also show signs of involvement. Patients who do not develop secondary syphilis still have latent syphilis, which refers to detectable T.pallidum serologies without signs or symptoms of active infection.
A 12-year-old girl presents with a patch of hair loss with fine scaling. Occipital adenopathy is present on examination. What treatment is indicated? Ketoconazole shampoo Oral griseofulvin Topical corticosteroids Topical nystatin
Correct Answer ( B ) Explanation: The child's presentation is consistent with tinea capitis. Tinea capitis is dermatophytic scalp infection caused by Trichophyton or Microsporum species. Dermatophyte infections are common in both immunocompetent and immunocompromised individuals, but rare presentations should raise suspicion of immunodeficiency. The most common presentation of tinea capitis is an irregularly defined patch of scaly skin that enlarges and later causes alopecia. The infection is often not noticed until alopecia occurs. Affected hair may also be broken, resulting in curved, "comma," hairs or corkscrew-shaped hairs. Occipital lymphadenopathy is often present. The lesion may also progress rapidly to a kerion. Diagnosis is confirmed on potassium hydroxide (KOH) preparation of scalp scrapings. In contrast to tinea corporis, eradication of tinea capitis requires oral antibiotic therapy. Oral griseofulvin has been a mainstay of treatment for children with tinea capitis and has an excellent safety profile. It is administered for six to 12 weeks. Terbinafine, although less studied in children, is an alternative therapy. Recently, randomized trials of shorter courses of oral fluconazole and itraconazole have shown similar efficacy to griseofulvin for the treatment of tinea capitis.
A 52-year-old woman is brought to the emergency department with burns from a house fire. Physical exam reveals superficial burns over her entire left arm and partial-thickness and full-thickness burns covering her entire right arm, her anterior right leg and anterior trunk. Which of the following percentages of total body surface area best estimates the extent of her burns? 18% 36% 45% 9%
Correct Answer ( B ) Explanation: The extent of burn size in this patient is 36% total body surface area. A thorough and accurate estimation of burn size is essential to guide therapy and to determine when to transfer a patient to a burn center. The extent of burns is expressed as the total percentage of body surface area. Superficial burns are not included in the burn assessment. For adult assessment, the most expeditious method to estimate total percentage of body surface area is the Rule of Nines. This method only takes into account partial-thickness and full-thickness burns. Each leg represents 18% total percentage of body surface area; each arm represents 9% total percentage of body surface area; the anterior and posterior trunk each represent 18% total percentage of body surface area; and the head represents 9% total percentage of body surface area. This patient has partial-thickness and full-thickness burns covering her entire right arm, her anterior right leg and anterior trunk, which calculates to 36%. The superficial burn on her left arm is not included in the calculation. According to the Rule of Nines, the percentage in this patient can be calculated as follows: entire right arm = 9%; anterior right leg = 9%; anterior trunk 18%. 9+9+18= 36%.
16-year-old girl is in the clinic because of bumps on her face. She noted these for the past couple of weeks that seem to worsen whenever she gets her period. On physical examination, there are multiple open and closed comedones on the nose and multiple erythematous papules and pustules on the nose and cheeks. Which of the following is the most likely diagnosis? Acne rosacea Acne vulgaris Perioral dermatitis Sebaceous hyperplasia
Correct Answer ( B ) Explanation: The girl has examination findings consistent with acne vulgaris. Acne vulgaris is the most common cutaneous disorder affecting adolescents and young adults. It is a disease of pilosebaceous follicles. Four factors are involved: follicular hyperkeratinization, increased sebum production, Propionibacterium acnes within the follicle, and inflammation. The microcomedo is considered the precursor for the clinical lesions of acne vulgaris, including closed comedones, open comedones, and inflammatory papules, pustules, and nodules. Acne vulgaris typically affects those areas of the body that have the largest, hormonally responsive sebaceous glands, including the face, neck, chest, upper back, and upper arms. Young adolescents often have primarily comedonal acne consisting of noninflammatory lesions (closed or open comedones) involving the forehead, nose and chin. And as the acne progresses, patients develop inflammatory lesions (papules, pustules, and nodules).
75-year-old woman with a history of sick sinus syndrome status post pacemaker implantation 2 weeks ago presents with pain over the pacemaker site and fever. Examination reveals erythema, warmth, fluctuance and tenderness over the pacemaker site. What management should be pursued? Incision and drainage of the site Intravenous antibiotics, cardiology consultation and admission Needle aspiration of the site Oral antibiotics and follow up with cardiology
Correct Answer ( B ) Explanation: The patient presents with a subcutaneous pacemaker "pocket" infection, which requires intravenous antibiotics, specialist consultation and admission. As with all surgical procedures, pacemaker implantation carries a risk for infection. This risk is small; about 2% for local wound infection and 1% risk for bacteremia or sepsis. Unfortunately, bacteremia is unlikely to respond to conservative management with antibiotics alone and replacement is often necessary. When either local infection or bacteremia is suspected, blood cultures should be obtained and intravenous antibiotics should be initiated. Staphylococcus aureus and Staphylococcus epidermidis are the most commonly isolated bacteria (60-70%). Thus, empirical antibiotics should include vancomycin. It is difficult to distinguish local infection from systemic infection and 20-25% of those with local infections will have positive blood cultures.
Which of the following is correct regarding the condition seen in the image above? Involvement of the scalp and nails is uncommon It is associated with the Auspitz sign Lesions most commonly occur on flexor surfaces Systemic steroids are the preferred treatment
Correct Answer ( B ) Explanation: The well-demarcated erythematous plaques and papules with silvery white scales are characteristic of psoriasis. Removal of the scale typically reveals pinpoint-bleeding areas referred to as the Auspitz sign. There is a hereditary predilection for the condition and often begins in the 2nd or 3rd decade of life.
A 3-day-old female developed a rash 1 day ago that has continued to progress and spread. The infant was born at term after an uncomplicated pregnancy and delivery to a healthy mother following excellent prenatal care. The infant was discharged 2 days ago in good health. She does not appear to be irritable or in distress, and she is afebrile and feeding well. On examination, abnormal findings are confined to the skin, including her face, trunk, and proximal extremities, which have macules, papules, and pustules that are all 2-3 mm in diameter. Her palms and soles are spared. A stain of a pustular smear shows numerous eosinophils. Which one of the following is the most likely diagnosis? Acne neonatorum Erythema toxicum neonatorum Herpes simplex virus keratitis Staphylococcal pyoderma
Correct Answer ( B ) Explanation: This infant has a typical presentation of erythema toxicum neonatorum. Erythema toxicum neonatorum (ETN) is a benign self-limited eruption occurring primarily in healthy newborns in the early neonatal period. Erythema toxicum neonatorum is characterized by macular erythema, papules, vesicles, and pustules, and it resolves without permanent sequelae. Acne neonatorum (A) consists of closed comedones on the forehead, nose, and cheeks. Staphylococcal pyoderma (D) is vesicular and the stain of the vesicle content shows polymorphonuclear leukocytes and clusters of gram-positive bacteria. Because the mother is healthy and the infant shows no evidence of being otherwise ill, systemic infections such as herpes (C) are unlikely.
A 45-year-old woman presents to the ED with the rash seen above. Which of the following is true regarding this condition? Always appears in a dermatomal distribution Firm stroking of the skin produces a wheal Mucous membrane involvement is commonly seen The rash is a mild form of Stevens-Johnson syndrome
Correct Answer ( B ) Explanation: This is an urticarial rash (hives). Urticaria may occur from a variety of agents, including foods (lobster, strawberry); drugs (penicillin, aspirin); infections (hepatitis, mononucleosis, coxsackie); change of temperature; and connective tissue disorders, to name a few. It can occur in isolation or as part of a systemic anaphylactic reaction. The characteristic rash appears as edematous plaques with pale centers and red borders. The rash of urticaria is transient, lasting less than 24 hours, though new lesions may continuously develop. Dermatographism is universally present and results in development of an urticarial wheal within 30 minutes of firm skin stroking. Mucous membrane involvement is pathognomonic of Stevens-Johnson syndrome (C and D) and may also be seen with anaphylaxis but is not typically seen with cases of simple urticaria.
A 22-year-old man presents to his primary care provider with a 2-week history of a rash that began as a single spot on his abdomen. Physical exam is notable for multiple macular lesions that are primarily located on the back. Most of the macules are approximately 1-2 cm in diameter with fine scales. A KOH preparation is negative. The patch on his abdomen has central clearing. Which of the following is the most likely diagnosis? Guttate psoriasis Pityriasis rosea Tinea corporis Tinea versicolor
Correct Answer ( B ) Explanation: This man most likely has pityriasis rosea. Pityriasis rosea is an acute, self-limiting, papulosquamous skin eruption that is commonly seen in otherwise healthy people. Pityriasis rosea is thought to be caused by a virus based on the occasional prodrome, clusters of cases, and pityriasis rosea is not associated with bacterial or fungal organisms. Pityriasis rosea is primarily seen in older children and young adults. Pityriasis rosea is slightly more common in women than in men. In 50-90% of cases, pityriasis rosea begins with a herald patch, a single, round, pink or salmon colored lesion with well demarcated edges. The herald patch is typically 2-5 cm in diameter with scales and central clearing. A small number of patients experience a prodrome of headache, malaise, and pharyngitis. A few days to two weeks later after development of the herald patch, similar but smaller lesions appear. These smaller lesions tend to be located on the trunk and are oriented along the lines of skin cleavage, creating a Christmas tree pattern. The rash resolves in four to six weeks in the majority of cases. Treatment involves reassurance and topical corticosteroids for pruritus, if present. Guttate psoriasis (A) presents with small, erythematous plaques that have coarser scales than pityriasis rosea. Guttate psoriasis does not have a preceding herald patch. In addition, a streptococcal infection frequently precedes guttate psoriasis.
A 34-year-old man presents to the emergency department with facial flushing, nausea, vomiting, and palpitations after eating tuna just one hour prior to presentation. His vital signs are T 36.7°C, HR 120 bpm, BP 130/70 mm Hg, and RR 18. On physical exam he appears diaphoretic and anxious. He has normal bowel sounds and no abdominal tenderness on exam. The rest of his exam is unremarkable. What is the most likely etiology of this patient's symptoms? A Ciguatera BHistamine fish poisoning CStaphylococcus DTetrodotoxin EVibrio parahaemolyticus
Correct Answer ( B ) Explanation: This patient's presentation is most consistent with histamine fish poisoning. Histamine fish poisoning is a food-related illness that occurs because of consumption of improperly stored fish. Bacteria on the surface of the fish decarboxylate histidine, a ubiquitous amino acid, forms a histamine. Commonly implicated fish include the following: tuna, mackerel, and mahi-mahi. When ingested, the histamine is absorbed and causes symptoms of flushing, headache, vomiting, abdominal pain, palpitations, and anxiety. Focal neurological findings are uncommon. The onset of symptoms is rapid, generally within the hour. Many species of fish can cause ciguatera poisoning (A), such as sea bass, grouper, and red snapper. Ciguatoxin increases neuronal sodium channel permeability leading to symptoms such as diaphoresis, headaches, abdominal pain, and cramps. Distinct neurologic symptoms, including the sensation of loose or painful teeth, parasthesias of the face and tongue, metallic taste, and reversal of temperature discrimination may also be reported. Staphylococcus (C) food poisoning is due to ingestion of a preformed toxin that leads to the onset of gastrointestinal symptoms (nausea, vomiting, diarrhea, and abdominal cramping) within 6 hours. Histamine-mediated symptoms do not occur. Tetrodoxin (D) is found in puffer fish and certain species of octopus. Marine bacteria that accumulate in fish produce the toxin, which inhibits sodium channels. Symptoms can occur within minutes, including headache, parasthesias, and facial nerve palsies. These may be followed by gastrointestinal disturbances and ultimately muscle weakness that progresses to an ascending paralysis. Death can occur from respiratory muscle paralysis. Care is supportive, and prolonged intubation may be required. Vibrio paraheamolyticus (E) infections are usually contracted by eating shellfish. Patients can present with nausea, vomiting, abdominal pain, diarrhea that may be bloody, fevers, and myalgias.
A 14-year-old boy presents with cracked, scaly skin in the interdigital webs of his feet. The remainder of his exam is benign. He recently began showering in the school locker room after football practices. What is the treatment of choice? Oral trimethoprim-sulfamethoxazole Topical clotrimazole Topical corticosteroids Topical nystatin
Correct Answer ( B ) Explanation: Tinea pedis, also known as athlete's foot, is a dermatophyte infection affecting the feet. The infection begins as vesicles or bullae on the toes or soles and may progress to significant scaling. Involvement of the interdigital webs is classic. Predisposing factors for tinea pedis include use of locker rooms and swimming pool facilities, where spores may be readily transmitted after shedding from infected individuals. Attacks are often self-limited but may recur after activities that involve significant sweating of the feet. Additionally, affected individuals may develop auto-eczematization, or an id reaction, in which papular eruptions occur over distant body sites. The etiology of id reactions is thought to be autoimmune. The diagnosis of tinea pedis can be microscopically confirmed with KOH preparation of scrapings of the affected skin. The treatment of choice is a topical antifungal, such as topical clotrimazole, for four weeks. Other options include other azoles, such as miconazole, or topical allylamines such as terbinafine or naftifine. Treatment of the primary infection also results in resolution of the id reaction. Notably, the cracked skin of tinea pedis is susceptible with Staph or Strep species, and thus signs of superinfection should be monitored.
A six-year-old otherwise healthy male presents to the urgent care center for a lesion on his scalp. The barber noticed a mass on the back of his head when his mother took him for a haircut four days prior. She has been applying topical creams that have not led to any improvement. She does not know the name of the creams. His mother reports the mass has become more painful, and there is noticeable hair loss at the site. Physical examination of the scalp reveals a boggy 10 cm x 10 cm erythematous occipital swelling with multiple pustules and crusting. There is marked circular alopecia of this area, which is tender to palpation. There is also post-auricular lymphadenopathy. Which of the following would be the likely diagnosis? Alopecia areata Impetigo Kerion Seborrheic dermatitis
Correct Answer ( C ) Explanation: A kerion is an inflammatory type of tinea capitis. The host develops a T-cell-mediated hypersensitivity response to the dermatophyte causing the fungal infection. The causative organisms are mainly Microsporum and Trichophyton. It typically presents as an inflammatory scalp mass with pustules and hair loss and may have the appearance of an abscess. Diagnosis is made by clinical appearance and can be confirmed, if necessary, by potassium hydroxide wet mount of plucked hairs and scales. Cultures may also be obtained of the plucked hairs, if needed. Wood's lamp may be used and will be diagnostic of Microsporum if fluorescent green. Treatment consists of oral antifungals. Griseofulvin is considered first line of treatment and may be needed for as long as eight weeks. Patients should be followed closely by their physician to ensure proper response. Terbinafine, fluconazole, and itraconazole are considered second-line if griseofulvin fails. Topical antifungals and antifungal shampoos may be used to reduce transmission but should not be considered as treatment. The use of steroids is thought by some to reduce the inflammatory process and help prevent permanent scarring and alopecia but is still controversial.
Which of the following rashes is seen in the above image? Erythema marginatum Erythema migrans Erythema multiforme Erythema nodosum
Correct Answer ( C ) Explanation: Erythema multiforme is an erythematous, papular rash that appears within 72 hours of the inciting cause. Although the feet, face and lower extremities may be involved, the hands and forearms are most commonly affected. Papules typically evolve into target lesions with a characteristic central dusky or purple zone surrounded by a pale ring and then a 3rd erythematous halo. Discrete oral lesions may be seen in approximately 50% of patients. Erythema multiforme is a type of hypersensitivity reaction in response to medications, infections, collagen vascular disorders, and malignancies. Common medications associated with erythema multiforme include sulfonamides, penicillins, barbiturates, and phenytoin. Common infections include herpes simplex and mycoplasma infections. The exact cause is unknown. The disorder is believed to involve damage to blood vessels of the skin with subsequent damage to dermal and epidermal tissues. Approximately 90% of erythema multiforme cases are associated with herpes simplex or Mycoplasma infections. The disorder occurs primarily in children and young adults.
An 18-year-old, obese woman presents to your office with a complaint of redness and pain in her left axilla. Physical exam reveals a solitary nodule, approximately 2 cm in size, with surrounding inflammation and erythema. She tells you that she's had similar "boils" in the past and that her mother had the same skin condition, which required surgery approximately 10 years after diagnosis. Which of the following is the most appropriate therapy? Finasteride Infliximab Topical clindamycin Topical clotrimazole
Correct Answer ( C ) Explanation: Hidradenitis suppurativa (HS) is a chronic inflammatory skin condition caused by a defect in the follicular epithelium. It is a progressive, disabling condition causing scarring, keloids, contractures, and immobility. Risk factors for the development of HS include obesity, genetics, smoking, diet, and mechanical stress on the skin. Onset occurs in adolescence or adulthood in previously healthy individuals. Diagnosis is a clinical one based on the appearance of the lesions, recurrence, and distribution. Initial treatment is with medical management and first-line treatment for stage I HS is localized treatment with topical clindamycin. Systemic medication or surgery is indicated for patients with severe or refractory cases.
A 23-year-old woman presents to the office with plaques on the extensor surfaces of her knees and elbows. She complains that the areas are itchy and they bleed after they are scratched. On exam, you also notice pitting of the fingernails. What is the most likely diagnosis? Erythema multiforme Lichen simplex chronicus Psoriasis Seborrheic Dermatitis
Correct Answer ( C ) Explanation: Psoriasis is an autoimmune condition with peak incidence in the early 20's. It occurs equally in males and females, and has a hereditary component. Stereotypical lesions are chronic, relapsing, thick silvery and scaly papules and plaques that overly an erythematous base. It is a chronic disorder but certain triggers such as infection, drugs, and trauma can cause flares. The Koebner phenomenon occurs when physical trauma elicits new growth of psoriatic patches. The most common areas affected are the extensor surfaces of the extremities (elbows and knees), lower back, palms and soles, scalp, gluteal cleft, and genital regions. Management is with glucorticoid topicals, UV-A therapy, and, in extreme cases, methotrexate and biologic medications.
A 23-year-old woman complains of headaches and arthralgias for the past 3 days. She presents to urgent care because of a painful rash on her face that has progressed into multiple vesicles. This rash is characterized by erythematous macules with dark purple centers with multiple vesicles in different stages. On physical exam there is also mucosal edema within the oral cavity. She recently completed an antibiotic course for a urinary tract infection. Which of the following is the most likely diagnosis? Erythema multiforme minor Staphylcoccal scalded skin syndrome Stevens-Johnson syndrome Toxic epidermal necrolysis
Correct Answer ( C ) Explanation: Stevens-Johnson syndrome is an immune-complex-mediated hypersensitivity reaction that typically involves the skin and the mucous membranes. After one to three weeks of exposure to the causative agent, a prodrome of fever, malaise, headache, cough, and conjunctivitis develops. Skin lesions appear one to three days after this prodrome. The lesions initially appear as erythematous macules with dark purpuric centers, then form atypical target lesions with central dusky purpura or a central bulla, with surrounding macular erythema. Mucosal involvement occurs in almost all affected patients. By definition, Stevens-Johnson syndrome affects less than 10% of the body surface area. Approximately 50% of cases of Stevens-Johnson syndrome are drug induced. Common causative agents include sulfa drugs, antiepileptic drugs, antibiotics, and nonsteroidal anti-inflammatory drugs. Steven-Johnson syndrome is a clinical diagnosis. The causative drug and any unnecessary medications should be discontinued. Aggressive management should include fluid resuscitation, nutritional supplementation, and wound care. Antibiotics should be used only if there is evidence of infection. Intravenous immune globulin has been incorporated into some treatment protocols. Complications include hypotension, renal failure, corneal ulcerations, anterior uveitis, erosive vulvovaginitis, respiratory failure, seizures, and coma.
A five-year-old boy is brought by his mother to clinic because of skin lesions. She noted these lesions a couple of weeks ago. The lesions do not seem to bother the boy. There is no pruritus, no erythema, and no fever. On physical examination vital signs are normal. On skin examination there are four firm, dome-shaped papules with central umbilication on the trunk measuring an average of 3 mm. Which of the following is the most likely diagnosis? Acrochordon Lichen planus Molluscum contagiosum Verruca vulgaris
Correct Answer ( C ) Explanation: The boy has skin lesions that are consistent with molluscum contagiosum. Molluscum contagiosum is due to a poxvirus that causes a chronic localized infection. It is a common disease of childhood. The disease also occurs in healthy adolescents and adults, often as a sexually transmitted disease or in relation to participation in contact sports. The lesions are characterized by firm, dome shaped papules on the skin. Lesions are often 2 to 5 mm in diameter, with a shiny surface and central indentation or umbilication. Occasionally, the growths can be polypoid with a stalk-like base. Pruritus may be present or absent, and lesions sometimes become visibly inflamed. It may appear anywhere on the body except the palms and soles. The most common areas of involvement include the trunk, axillae, antecubital and popliteal fossae, and crural folds. The diagnosis of molluscum contagiosum is usually made by the characteristic appearance of the lesions. When necessary, histologic examination can confirm the clinical diagnosis. Hematoxylin and eosin staining of a molluscum contagiosum lesion typically reveals keratinocytes containing eosinophilic cytoplasmic inclusion bodies (also known as molluscum bodies or Henderson-Patterson bodies).
Which of the following diseases presents with small grouped vesicles on an erythematous base? Aphthous ulcer Dyshidrotic eczema Herpes simplex Impetigo
Correct Answer ( C ) Explanation: The herpes simplex viruses comprise 2 distinct types of DNA viruses: herpes simplex virus (HSV)-1 and HSV-2. HSV-1 causes oral lesions in approximately 80% of cases and genital lesions in 20% of cases. The reverse is true for HSV-2, which causes genital lesions in 80% of cases and oral lesions in 20% of cases. Herpetic lesions are classically described as small grouped vesicles on an erythematous base (dew drop on a rose petal). Aphthous ulcer (A) is a common noncontagious mouth ulcer also referred to as a canker sore. The cause is not completely understood but may involve a T cell-mediated immune response triggered by a variety of factors. These are ulcers and do not contain vesicles.
An eight-year-old girl presents with her father to the clinic because of itchy bumps on her legs. Yesterday, there were a few bumps on the girl's legs, which she has been constantly scratching. She did recall that she had insect bites on her legs a month ago when she went hiking with her brother and father although she has not had any insect bite recently. On skin examination, there are multiple 0.5 cm to 1 cm papules with central crusts and excoriations on both her legs. Which of the following is the most likely diagnosis? Atopic dermatitis Langerhans cell histiocytosis Papular urticaria Scabies
Correct Answer ( C ) Explanation: The girl has history and examination findings that are consistent with papular urticaria. Papular urticaria is a hypersensitivity disorder in which insect bites, most often those of fleas, mosquitoes, or bedbugs, lead to recurrent and sometimes chronic itchy papules on exposed areas of skin (like the arms, lower legs, upper back, and scalp). Papular urticaria is reported predominantly in young children (typically two to 10 years of age). The diaper areas, genital, perianal, and axillary areas are spared. The 0.5 to 1 cm lesions may be urticarial at the start of the syndrome, but become persistent and papular or nodular with time. The diagnosis of papular urticaria is made clinically, although there may be a delay between the inciting bite and the onset of lesions, or insect bites may not have been noticed at all. Usually only one child in a family is affected, a clue that infestation at home is unlikely. New lesions may appear sporadically, and renewed itching may lead to reactivation of older lesions, leading to a chronic and cycling disorder that may last from months to years. Management of papular urticaria includes selective and limited use of non-sedating antihistamines for pruritus, mid-potency topical corticosteroids applied to individual lesions, and reassurance, as the disorder eventually resolves spontaneously.
A 13-year-old boy presents with fever, arthralgias, lympadenopathy and pruritus 7 days after starting phenytoin for a newly diagnosed seizure disorder. What type of hypersensitivity reaction explains the patients symptoms? Type I Type II Type III Type IV
Correct Answer ( C ) Explanation: The patient is suffering from a serum sickness-like reaction caused by phenytoin, which is a type III hypersensitivity reaction. Type III hypersensitivity reactions are immune complex-mediated reactions. Antibodies bind to antigens to form immune complexes. These are deposited on vessel walls leading to local inflammation and eventually tissue injury. Type III reactions are seen in systemic lupus erythematosus and serum sickness. Serum sickness presents with rash, fever, polyarthralgias and polyarthritis usually begins 1-2 weeks after exposure to a causative agent.
A patient presents with a diffuse rash for 1 day as seen above. The patient also describes painful lesions on his lips. Which of the following treatments should most likely be initiated? Diphenhydramine Epinephrine Systemic corticosteroids Topical corticosteroids
Correct Answer ( C ) Explanation: This patient presents with a rash consistent with erythema multiforme (EM) and should be started on systemic corticosteroids. EM is an acute disease caused by the sudden appearance of erythematous violaceous macules and papules. It is usually self-limiting. The rash is commonly found on the soles of the feet and the palms of the hands. Lesions are target-like with a central dark papule surrounded by a pale area and a "halo" of erythema. Although the majority of cases of EM are self-limiting, they occasionally progress to Stevens-Johnson syndrome, which is life-threatening. Mild cases of EM do not require treatment. Oral antihistamines and topical steroids may be used to provide symptom relief. In patients with coexisting or recent HSV infection, early treatment with oral acyclovir may lessen the number and duration of cutaneous lesions. More severe cases (significant mucous membrane involvement) should be treated with systemic corticosteroids. In addition, the patient should receive supportive care with pain medication and hydration. If possible, try to identify the underlying cause.
A 52-year-old woman presents to her primary care provider's office with complaints of a pruritic rash on her chest. She has a past medical history of morbid obesity, type 2 diabetes mellitus, and hypertension. On exam, there is a sharply demarcated area of erythema underneath both breasts. Direct microscopy of skin scrapings reveals oval budding yeast and pseudohyphae. Which of the following is the most appropriate management? Oral fluconazole Oral prednisone Topical econazole Topical mupirocin
Correct Answer ( C ) Explanation: This woman, with limited areas of candidal intertrigo, is best treated with topical econazole. Intertrigo is an inflammatory condition of two opposed skin surfaces or folds. Intertrigo can be infectious or noninfectious. The inflammatory process is induced by heat, friction, moisture, and lack of air circulation. The resulting skin breakdown creates a warm, moist environment that is ideal for overgrowth of microorganisms. While bacteria can cause intertrigo, the most common etiology is a superficial infection of Candida species. Risk factors for candidal intertrigo include obesity, tight-fitting clothing, hyperhidrosis, urinary or fecal incontinence, diabetes mellitus, topical or systemic corticosteroid use, antibiotic use, human immunodeficiency virus (HIV) infection, and chemotherapy. Patients with recurrent or severe candidal infections without an obvious cause should undergo further evaluation for underlying or undiagnosed endocrinopathy, malignancy, or HIV infection. Candidal intertrigo is typically located in inguinal folds, axillae, scrotum, inframammary folds, beneath a pannus, or intergluteal folds. The involved area appears erythematous and macerated with satellite papules and pustules. The plaques are usually pruritic. The diagnosis of intertrigo is mainly clinical, but potassium hydroxide (KOH) examination or direct microscopy can be used to confirm the diagnosis. Treatment involves antifungal medication, skin care, and addressing predisposing risk factors. Topical antifungal medication is effective and well tolerated in most patients with mild to moderate infections. Oral agents may be required when topical therapy has failed or if there are multiple intertriginous areas involved. Skin care with drying agents is important for preventing recurrences of intertrigo. Commonly used drying agents are antifungal powders, like nystatin. Weight loss, loose clothing, and absorbent hygiene products may be useful preventative measures.
A 15-year-old boy presents to clinic with his mother with acne on his forehead and nose. He has been using over the counter facial scrubs without relief. Physical exam shows multiple closed comedones with mild inflammation on the forehead and nose. He has no significant past medical history and does not smoke or consume alcohol. What is the most appropriate initial pharmacologic therapy? Benzoyl peroxide Oral antibiotic Oral retinoid Topical retinoid
Correct Answer ( D ) Explanation: Answer D. This patient has mild comedonal acne vulgaris. Acne vulgaris is classified by four lesions: open and closed comedones, papules, pustules and nodulocystic lesions. The mildest form is associated with comedones on the central area of the face. Topical retinoids are the primary treatment for acne vulgaris. They act by inhibiting the formation of microcomedones, reduction of mature comedones and decreasing inflammation. They should be applied daily to all lesions. The most common side effect is dryness and irritation. Initial control of symptoms takes at least 6-8 weeks depending on the severity.
A 42-year-old woman presents to her primary care provider's office complaining of intermittent facial flushing worsened by alcohol and exercise. Physical exam is notable for bright, erythematous papules with overlying pustules and telangiectasia on her cheeks and nose. No comedones are present. Which of the following is the most likely diagnosis? Acne vulgaris Cutaneous lupus erythematosus Dermatomyositis Rosacea
Correct Answer ( D ) Explanation: The woman in this case most likely has rosacea. Rosacea can be classified into four different subtypes: erythematotelangiectatic, papulopustular, phymatous, and ocular rosacea. Rosacea is most commonly seen in fair-skinned individuals and in women. Presentations and clinical findings vary based upon subtype and patients may present with one or multiple subtypes. Erythematotelangiectatic rosacea typically presents with persistent centrofacial erythema, flushing, telangiectasias, and rough, dry, sensitive skin. Papulopustular rosacea is characterized by inflammatory papules and pustules that are primarily localized to the central face. Phymatous rosacea is marked by hypertrophied skin with irregular contours. Phymatous rosacea most commonly affects the nose (rhinophyma). More than half of patients with rosacea have ocular involvement. Ocular rosacea manifestations include hyperemia, anterior blepharitis, keratitis, photosensitivity, and burning or stinging. Patients may notice exacerbations due to temperature exposure, sun exposure, hot beverages, spicy food, alcohol, exercise, or topical products. Diagnosis is based on clinical findings and biopsy is rarely indicated. General management for all subtypes should involve avoidance of triggers, gentle skin care, and sun protection. Erythematotelangiectatic rosacea can be treated with topical brimonidine. Topical metronidazole is recommended for patients with papulopustular subtype. Patients with ocular symptoms should be referred to an ophthalmologist.
One Step Further Question: Which gender predominates in newly diagnosed cases of Celiac disease?
Answer: Up to 75% of new cases of Celiac disease are diagnosed in women.
Which of the following sutures is absorbable? Nylon (Polyamide) Prolene (Polypropylene) Silk (Silk) Vicryl (Polyglactin)
Correct Answer ( D ) Explanation: Absorbable sutures are degraded and lose strength in less than 60 days. Absorbable sutures are generally used for subcutaneous and mucosal closures. Their highly reactive nature allows them to be broken down and absorbed over weeks. Vicryl is an absorbable braided polymer of lactide and glycolide with low reactivity and good strength making it suitable for subcutaneous and mucous membrane use. Prolene (B), Nylon (A), and Silk (C) are nonabsorbable.
One Step Further Question: What are the manifestations of tertiary syphilis?
Answer: Neurosyphilis, cardiovascular involvement, and gumma formation.
One Step Further Question: What are the most common sites of metastatic disease with melanoma?
Answer: Brain, liver, and bone.
One Step Further Question: What is the treatment of choice for Rocky Mountain Spotted Fever in the pediatric population?
Answer: Doxycycline. Regardless of the side effects that doxycycline can cause in the pediatric population, the benefits far outweigh the risks
One Step Further Question: The most commonly occurring insect bites are inflicted by mosquitoes of which family?
Answer: Family Culicidae (order Diptera).
One Step Further Question: What is the most common complaint of patients with lupus?
Answer: Fatigue
One Step Further Question: What is the name and causative agent of the fifth common childhood exanthemous disease?
Answer: Fifth disease or Erythema Infectiosum caused by parvovirus B19 is the fifth of the classic childhood exanthems
One Step Further Question: What is the classic dermatologic finding of tertiary syphilis?
Answer: Gummas.
One Step Further Question: Which groups of patients are at increased risk of developing herpetic whitlow?
Answer: Health-care workers (e.g. physicians, nurses, dentists, and dental assistants) and nail salon workers.
One Step Further Question: What is the treatment of choice in those who develop Erythema multiforme?
Answer: In most cases of EM, supportive treatment is all that is necessary. Oral antihistamines, steroids, and analgesics may be beneficial.
One Step Further Question: Is the rash of pityriasis rosea contagious?
Answer: No, the rash cannot be spread by direct contact.
One Step Further Question: What is the recommended systemic treatment for perioral and periorbital dermatitis?
Answer: Oral tetracyclines, such as doxycycline.
One Step Further Question: When are patients with herpes zoster considered to no longer be infectious?
Answer: Patients are no longer considered infectious once the herpes zoster lesions are crusted over.
One Step Further Question: What medication is indicated for the treatment and prevention of head lice and scabies?
Answer: Permethrin.
One Step Further Question: Which medications commonly used to treat condyloma accuminata should be avoided during pregnancy?
Answer: Podophyllin, podophyllotoxin, and imiquimod.
One Step Further Question: What is a known, transient complication of seborrheic dermatitis in dark-pigmented infants?
Answer: Postinflammatory hypopigmentation.
One Step Further Question: What is the characteristic finding consistent indicative of corneal ocular involvement in zoster ophthalmicus?
Answer: Pseudodendrites (no terminal bulb).
One Step Further Question: Why should fluorodinated corticosteroids not be applied to the face?
Answer: Repeated use can produce permanent cutaneous atrophy.
One Step Further Question: What is the recommended treatment for dyshidrotic ecematous dermatitis?
Answer: Steroids can be administered topically, intralesionally or systemically depending on the severity. PUVA (psoralen and UVA light) may also be beneficial.
One Step Further Question: Which microbes would be necessary to empirically cover for in choosing an antibiotic treatment for uncomplicated cellulitis?
Answer: Streptococcus and Staphylococcus.
One Step Further Question: What has a greater risk of infection, cutaneous or subcutaneous sutures?
Answer: Subcutaneous.
One Step Further Question: Why is trimethoprim-sulfamethoxazole (TMP-SMX) a poor choice as a single agent to treat cellulitis?
Answer: TMP-SMX is active against most methicillin resistant Staphylococcus aureus but has poor coverage against group A streptococci; an organism often implicated in cellulitis
One Step Further Question: What is a common complication within 24 hours of initiation of antibiotic treatment of Lyme disease?
Answer: The Jarisch-Herxheimer reaction.
One Step Further Question: What distinguishes chickenpox from smallpox?
Answer: The crops of smallpox all develop with the same timing whereas in chickenpox they present in various stages.
One Step Further Question: Where are the most commonly involved sites of HPV infection in men?
Answer: The penis and scrotum.
A 37-year-old man with a past medical history of type 2 diabetes mellitus presents with complaints of pain and increasing redness and swelling of his right lower leg. He reports fever and chills. Physical exam reveals a temperature of 101° F with local tenderness, erythema with indistinct flat borders and moderate edema involving the right lower leg. Inguinal lymph nodes are non-palpable and there is no evidence of lymphatic streaking. Which of the following is the most likely diagnosis? Cellulitis Erysipelas Mucocutaneous candidiasis Necrotizing fasciitis
Correct Answer ( A ) Explanation: Cellulitis is characterized by an expanding, erythematous, edematous and tender lesion often involving the lower extremity. The borders of the area involved are not elevated and not demarcated. Borders of erythema should be marked in order to track spread of infected tissue. Pain, chills, and fever are commonly present. Diabetes mellitus is one of the risk factors for development of this disease. Delay in appropriate prompt antibiotic treatment may result in septicemia.
An 18-year-old man is diagnosed with condyloma acuminatum in the genital area. Which of the following physical exam findings is most consistent with this diagnosis? Flesh-colored, exophytic lesions Painless ulceration Shallow, painful ulcerations Umbilicated, dome-shaped lesions
Correct Answer ( A ) Explanation: Condyloma acuminata, commonly known as genital warts, can appear as flesh-colored, exophytic lesions or can appear as small bumps that are flat, pedunculated, verrucous, or papilliform. Condyloma acuminatum is caused by an infection with the human papillomavirus (HPV) types 6 and 11. It is a sexually transmitted infection that can be prevented with vaccination. All girls and boys who are 11 or 12 years old should get the recommended series of HPV vaccine regardless of sexual history. HPV is strongly associated with the development of genitourinary and rectal cancer. The infection can affect the vagina, cervix, vulva, oropharynx, perineum, and perianal areas. Treatment includes trichloroacetic acid solution, podophyllin, cryosurgery, surgical excision, or imiquimod cream application.
One Step Further Question: What rashes commonly appear on the palms?
Answer: Erythema multiforme, drug eruption, secondary syphilis, Rocky mountain spotted fever, hand-foot-and-mouth disease, scabies.
One Step Further Question: How is erythema toxicum neonatorum diagnosed?
Answer: Erythema toxicum neonatorum (ETN) is diagnosed clinically based on history, physical examination, and peripheral smear of intralesional contents.
One Step Further Question: What are criteria for admitting a patient with cellulitis on outpatient antibiotics?
Answer: Failure to improve or worsening cellulitis after 48-72 hours of appropriate therapy.
One Step Further Question: True or false: surgical removal of a nail infected with onychomycosis provides a definitive cure?
Answer: False.
One Step Further Question: What other antiviral medications are used in the treatment of herpes zoster infection?
Answer: Famciclovir and valacyclovir
One Step Further Question: Which type of malignancy is most associated with malignant acanthosis nigricans?
Answer: Gastric cancer.
One Step Further Question: Which gastrointestinal malignancy is associated with acanthosis nigricans?
Answer: Gastric carcinoma.
One Step Further Question: Greater than what total body surface area (TBSA) is diagnostic of toxic epidermal necrolysis?
Answer: Greater than 30%.
One Step Further Question: What term was historically used to describe lichen simplex chronicus?
Answer: Neurodermatitis.
One Step Further Question: In what circumstance is dry heat recommended in the treatment of frostbite?
Answer: None. Dry heat may cause further injury.
One Step Further Question: What additional management is indicated in a bite from a dog with unknown immunization status?
Answer: On initial presentation, the patient should have rabies immunoglobulin administered and should have the rabies vaccination series started.
One Step Further Question: What two conditions promote growth of condyloma acuminatum?
Answer: Pregnancy and immunosuppression.
One Step Further Question: What conditions commonly cause false positive PPD results?
Answer: Prior infection with nontuberculous mycobacteria and a history of a bacilli Calmette-Guerin (BCG) vaccination
One Step Further Question: What common infection is known to trigger eruptive, inflammatory psoriasis?
Answer: Streptococcal Pharyngitis.
One Step Further Question: What is the most serious long-term complication of measles infection?
Answer: Subacute sclerosing panencephalitis.
One Step Further Question: Dyshidrotic eczema flares are more frequent in which season?
Answer: Summer.
One Step Further Question: What is a common complication of oral lichen planus?
Answer: Superficial candidal infection.
One Step Further Question: What is the recommended method of burn assessment in children?
Answer: The Lund-Browder chart is the recommended method because it takes into account the relative percentage of body surface area affected by growth.
One Step Further Question: Erythroplasia of Queyrat is used to describe squamous cell carcinoma in what location?
Answer: The penis.
One Step Further Question: Which fungal infection may present with areas of pink or white macules, commonly on the upper torso, that may be confused with vitiligo in patients of dark complexions?
Answer: Tinea versicolor may present as pale macules that do not tan, commonly on the upper trunk.
One Step Further Question: What is a first line treatment for psoriasis?
Answer: Topical corticosteroids.
One Step Further Question: The "wire brush" feel is characteristic of what hair loss condition?
Answer: Trichotillomania.
One Step Further Question: What is the treatment of choice for erysipelas caused by methicillin-resistant Staphylococcus aureus?
Answer: Trimethoprim-sulfamethoxazole, clindamycin.
One Step Further Question: How is a previously vaccinated person who has had a potential rabies exposure treated?
Answer: Two intramuscular doses of vaccine; the first dose should be given on day 0, as soon after exposure as possible, and the other three days later.
One Step Further Question: What type of hypersensitivity reaction is the immediate development of urticaria after an ingestion?
Answer: Type I.
One Step Further Question: What layer of skin edema defines urticaria?
Answer: Urticaria involves localized dermal edema produced by transvascular fluid extravasation.
One Step Further Question: What are some methods to decrease pain associated with injection of lidocaine?
Answer: Warming the solution, buffering the solution with sodium bicarbonate, and injecting into the wound rather than through intact skin.
One Step Further Question: What is the phenomena of "core temperature after-drop" in frostbite management?
Answer: When large areas are rewarmed, vasoconstriction is relieved and cold, hyperkalemic and acidic blood returns to the central circulation.
One Step Further Question: What is the definition of Stevens-Johnson/toxic epidermis necrolysis?
Answer: When the body surface area involved in 15-30%.
One Step Further Question: What tool may be helpful for identifying vitiligo in lightly pigmented individuals?
Answer: Wood lamp.
One Step Further Question: Can the alopecia associated with a kerion become permanent?
Answer: Yes, if left untreated, a kerion can lead to permanent alopecia.
One Step Further Question: Can tinea corporis be transferred person-to-person?
Answer: Yes.
One Step Further Question: Does smoking increase the risk of basal cell carcinoma?
Answer: Yes.
One Step Further Question: Can succinylcholine be used for rapid sequence intubation in an acute burn patient?
Answer: Yes. The concerning change in muscle receptors that occurs from burns takes place over 7-10 days after the burn
One Step Further Question: What structure does the fungi invade first to gain access to nail bed?
Answer: hyponychium. Candida albicans (A) is the most common cause of fingernail onychomycosis. Yeast more frequently affects fingernails than toenails. Candida albicans is a common commensal organism normally found in the human oropharyngeal cavity, gastrointestinal tract, and vagina.
One Step Further Question: Which variant of acne vulgaris presents with fever and arthralgias with an acute eruption of large inflammatory nodules and friable plaques with hemorrhagic crusts?
Answer: Acne fulminans.
One Step Further Question: What is the other name for hidradenitis suppurativa?
Answer: Acne inversa.
One Step Further Question: What is the incubation period for molluscum contagiosum?
Answer: Between two to six weeks.
One Step Further Question: What is the Jarisch-Herxheimer reaction?
Answer: A febrile reaction to antigens that are liberated when spirochetal bacteria (classically syphillis) are destroyed by antibiotic therapy.
One Step Further Question: What are the two most aggressive forms of acne?
Answer: Acne fulminans and acne conglobata.
Smooth, circular, discrete patches of hair loss, characterized by short broken "exclamation point" hairs at the margins, are most consistent with which diagnosis? Alopecia areata Cicatricial alopecia Tinea capitis Trichotillomania
Correct Answer ( A ) Explanation: Alopecia areata is an autoimmune form of nonscarring hair loss. "Exclamation point hairs," which are short broken hairs for which the proximal end of the hair is narrower than the distal end, are pathognomonic for alopecia areata. There are no epidermal changes to the skin during alopecia areata, so the region of hair loss remains smooth. Intralesional injections of corticosteroids are the treatment of choice and most recover from the hair loss within a year.
A 70-year-old woman presents to the Emergency Department with the complaint of blisters on her abdomen for the past month. Initially the rash was composed of small pruritic papules which developed into bullae after three weeks. Some of the blisters recently broke and are now tender eroded lesions as shown in the above image. There is no mucosal involvement. When lateral pressure is applied, the bullae do not enlarge. She denies trauma, exposure to new chemicals, starting new medications, or recently hiking outdoors. What is the most likely diagnosis? Bullous pemphigoid Pemphigoid vulgaris Pustular psoriasis Stevens-Johnson syndrome
Correct Answer ( A ) Explanation: Bullous pemphigoid is the most common bullous autoimmune disease of the elderly. The age of onset is between 60-80 years old and it affects men and women equally. The lesions begin as pruritic papules, which early in the disease course can be easily confused with urticaria. However, unlike urticaria, they do not change position. The papules coalesce into large tense bullae over weeks to months and exhibit a negative Nikolsky sign (they do not easily extend when lateral pressure is applied). The bullae appear on normal or erythematous skin and eventually rupture leaving tender eroded lesions. The underlying cause is the production of autoantibodies to basement membrane proteins, basal keratinocyte hemidesmosomal antigens, which cause a detachment at the basement membrane between the epidermis and dermis. Commonly affected body regions include the axilla, medial aspect of the thigh, groin, abdomen, forearm flexors, and lower extremities. They may also be generalized. Mucous membranes are almost never involved. The painful eroded lesions crust and eventually heal spontaneously. Oral steroids are the mainstay of treatment and help to hasten resolution. Recurrence is rare but can occur.
A 23-year-old man presents with multiple skin papules on his inner thighs, groin, and penis. The papules are about 3 mm in diameter, have a central indentation, and are nontender. A small amount of caseous material can be expressed from the papules. Which of the following is the most appropriate therapy? Cryotherapy Oral acyclovir Reassurance and watchful waiting Topical mupirocin
Correct Answer ( A ) Explanation: For patients who desire treatment or who have suspected sexually transmitted molluscum contagiosum, treatment options include cryotherapy, keratolytics, and curettage. Molluscum contagiosum is a local infection caused by a poxvirus. Molluscum contagiosum is commonly seen in children. Molluscum contagiosum can also be seen in adolescents and adults as a sexually transmitted disease or due to contact sports. Molluscum contagiosum is spread by direct skin-to-skin contact, through autoinoculation, or through contact with contaminated fomites. Molluscum contagiosum typically presents with firm, dome-shaped papules that are 2-5 mm in diameter. The papules are shiny and have a central umbilication. The lesions may occasionally be visibly inflamed. Molluscum contagiosum can occur anywhere on the body except for the palms and soles. Eyelid lesions can induce conjunctivitis. Sexually transmitted molluscum contagiosum usually appears on the groin, genitals, inner thighs, and lower abdomen. Laboratory studies are unnecessary in children, but sexually active adolescents and adults with genital lesions should be tested for other sexually transmitted diseases. Extensive lesions should raise the suspicion for human immunodeficiency virus infection. Options for treatment include benign neglect, cryotherapy, curettage, or keratolytics. Benign neglect is often recommended because molluscum contagiosum is typically benign and lesions heal within 1-2 months. Treatment is recommended for teenagers and adults with suspected sexually transmitted infections due to risk of transmission.
A 65-year-old woman who is morbidly obese presents to your office with intertrigo in the axilla. On examination you detect small, reddish-brown macules that are coalescing into larger patches with sharp borders. You suspect a secondary infection complicating the intertrigo. What is the most appropriate topical treatment for this condition? Erythromycin Mupirocin Nyastatin Zinc oxide
Correct Answer ( A ) Explanation: Intertrigo is a superficial inflammatory dermatitis occurring on two closely opposed skin surfaces as a result of moisture, friction, and lack of ventilation. Bodily secretions, including perspiration, urine, and feces, often exacerbate skin inflammation. Physical examination of skin folds reveals regions of erythema with peripheral scaling. Excessive friction and inflammation can cause skin breakdown and create an entry point for secondary fungal and bacterial infections, such as Candida, Group A beta-hemolytic streptococcus, and Corynebacterium minutissimum. Cutaneous erythrasma is caused by Corynebacterium minutissimum and presents as small reddish-brown macules that may coalesce into larger patches with sharp borders. They may be asymptomatic or pruritic and fluoresces coral-red on Wood lamp examination. Intertrigo complicated by erythrasma is treated with topical or oral erythromycin
An 18-year-old woman presents complaining of perioral dermatitis that she has experienced for the past two weeks. She states it has recently started itching and burning. What is the best treatment for this condition? Isotretinoin cream Metronidazole gel Oral prednisone Triamcinolone cream
Correct Answer ( B ) Explanation: Perioral dermatitis is defined by discrete erythematous micro-papules and microvesicles that concentrate in the perioral, and occasionally periorbital, area. These lesions often last weeks to months and sometimes cause an itching or burning sensation. It may occur in all ages, but affects women more commonly than men. Diagnosis is clinical, though it might be beneficial to culture the lesions to rule out a S. aureus infection. While the etiology is unknown, perioral dermatitis is known to be aggravated by topical glucocorticoids. Metronidazole gel or erythromycin gel is first-line topical treatment for perioral dermatitis. Oral prednisone (C) works to systematically reduce inflammation, but is not indicated to treat perioral dermatitis. Triamcinolone cream (D) is a topical steroid that has been shown to exacerbate perioral dermatitis.
A 39-year-old woman with a history of Hashimoto thyroiditis presents for recent hair loss. An exam, she has several perfectly smooth bald patches on her scalp with a few short hairs growing in each patch. Which of the following interventions is most likely to improve her condition? Prescribe intralesional triamcinolone Prescribe iron supplementation Prescribe topical minoxidil Refer for psychiatric counseling
Correct Answer ( A ) Explanation: Intralesional corticosteroids, such as triamcinolone, are commonly effective for managing alopecia areata, which this patient appears to have. Alopecia areata is thought to be an immunologic process by which patients develop patches of smooth, nonscarring hair loss on their scalp that may progress to include facial hair (alopecia totalis) or involve all body hair (alopecia universalis). These patches often contain growth of several 2-3 mm hairs termed "exclamation hairs." Alopecia areata may occur in patients with a history of autoimmune-related disorders, such as Hashimoto thyroiditis, Addison disease, vitiligo, or pernicious anemia. Intralesional corticosteroids usually offer some resolution of the hair loss. Systemic steroids may be used in severe cases, though hair loss generally resumes once they are discontinued. Patients should be reassured that this disease usually resolves spontaneously regardless of treatment, and that 80% of patients with focal disease will have complete hair regrowth. However, the psychological impact of alopecia areata can be significant and patients may benefit from a referral to local supportive groups.
Which of the following is concerning for melanoma? Areas of pigment regression Other similar lesions Pearly border Regular border
Correct Answer ( A ) Explanation: Melanoma is a highly aggressive malignancy of melanocytes in the skin. Although it is the least common skin malignancy, it has the highest mortality. The peak incidence occurs in 20- to 45-year-olds which is much younger than the other two forms of skin cancer (basal cell carcinoma and squamous cell carcinoma). Any new mole after age 35 needs a dermatologic evaluation since people rarely form new moles at this age. The mnemonic ABCDE helps to remember the characteristics of melanoma: Asymmetry, Border (irregular), Color (different shades, not uniform), Diameter (>6 mm), Evolution. Areas of pigment regression describe changes in color and a lack of uniformity of the lesion. A pearly border (C) is more consistent with a basal cell carcinoma. These lesions often begin as a pearly papule with telangiectasias. Regular borders (D) are uncommon as the malignancy does not grow in a uniform pattern.
Which of the following is responsible for lice infestation of the head and scalp? Pediculus humanus capitis Pediculus humanus corporis Piedraia hortae Pthirus pubis
Correct Answer ( A ) Explanation: Pediculus humanus capitis is the head louse responsible for pediculosis capitis, a condition caused by infestation of the scalp and hair. Also referred to as lice or lice infestation, pediculosis capitis is very common worldwide and most frequently affects children. The female louse lays eggs and attaches them to the base of the hair shaft. These eggs, or nits, are easily seen without magnification on physical exam. They are most commonly found behind the ears or at the posterior hairline. Nits take 8-9 days to hatch and 9-12 days to mature. The average lifespan of Pediculus humanus capitis is 30 days. Potential infestations often come to the attention of parents by school officials who send advisories home due to the contagious nature of lice. Parents and teachers often make the diagnosis of lice by seeing nits or live insects and the patient comes to the medical office for confirmation and treatment recommendations. Treatment is with topical pediculicides and a second treatment should be applied nine days after the first to ensure eradication. Pediculus humanus corporis (B) is the louse responsible for body lice. The body louse is larger than the head louse and does not live on the human body like Pediculus humanus capitis does. Instead it lives in clothing and crawls onto the human body to feed, then retreats. Piedraia hortae (C) is a fungal infection found in tropical climates that presents with white, brown, or black concretions on the hair shaft. It is on the differential along with lice for individuals with a travel history or who live in a tropical climate. Pthirus pubis (D) is the louse responsible for pubic lice or crabs. Infestations with pubic lice are generally sexually transmitted with severe infestations also affecting the axillae and facial hair.
A 40-year-old man presents to your office with a complaint of a spider bite. He was chopping wood at his house, looked down, and saw a spider bite his leg. In addition to pain, his symptoms include muscle aches in his legs and back, severe abdominal pain, tremor, weakness, nausea, and vomiting. Which of the following is the most likely cause of his symptoms? Black widow spider Brown recluse spider Redback spider Wolf spider
Correct Answer ( A ) Explanation: Spider bites are rare and very few species of spider cause problems for humans. A number of more common disorders present with similar symptoms to a spider bite, such as skin infections and bites of other insects, therefore accurate diagnosis is the first goal in managing these patients. Black widow spiders are found throughout North America and can be identified with the classic red hourglass on the underside of the abdomen. These spiders are shy and solitary and generally are found in undisturbed places such as woodpiles, garages, or barns. They do not bite unless provoked. Widow spider venom is neurotoxic, and systemic symptoms include muscle aches, abdominal pain, tremor, weakness, nausea, and vomiting. Treatment approach depends on the severity of symptoms and response to initial supportive care. Antivenom is indicated for moderate to severe symptoms that do not respond to parenteral opioids and benzodiazepines. Patients with persistent severe pain and symptoms that do not respond to antivenom need hospitalization. Brown recluse spiders (B) are found in the geographic area encompassing central Texas to Tennessee and southern Illinois to Florida. Their venom is hemolytic and cytotoxic causing an intense inflammatory response. Within several hours of the bite, patients experience pain and pruritus with resulting ischemia and skin necrosis. The redback spider (C) is found in Australia and is a relative of the black widow spider found in North America. This spider is black with a red stripe on the dorsal aspect of the abdomen. Its venom is neurotoxic with bites causing localized pain, erythema, and some systemic symptoms including nausea, vomiting, headache, and arthralgias. Antivenom is available for severe cases. Wolf spiders (D) are found throughout the world, are fast, and can chase after prey. Wolf spiders generally run away when threatened and most are harmless. Bites cause pain that lasts a short time and very rarely cause systemic effects.
A 34-year-old man presents with alcohol intoxication and left hand pain. The patient states that he fell asleep on the sidewalk in the snow. Examination reveals a swollen, erythematous left hand with clear blisters as seen above. The patient has decreased sensation and decreased range of motion. What therapy is indicated? Place hand in warm (37°C/98.6°F - 39°C/102.2°F) circulating water Place hand under hot (45°C/113°F - 52°C/125.6°F) running water Warm hand with circulating hot air Wrap hand in warm blankets
Correct Answer ( A ) Explanation: The patient presents with severe frostbite to the left hand from exposure and will require gentle, active rewarming of the extremity. During cold exposure, vasoconstriction occurs in an effort to conserve heat. As the temperature drops below 10°C, cutaneous sensation is compromised. With microvascular vasoconstriction, plasma begins to leak into the interstitial space. Ice crystals begin to form once the temperature approaches 0°C. Once crystals begin forming, intracellular osmolarity rises and cells begin to collapse and die. Blood flow begins to sludge followed by stasis and cessation of flow at the capillary level. Patients will often present with pain and decreased sensation (75%) but usually do not have frank frozen and insensate tissue. Frostbite, like burns, is classified into degrees of injury. First-degree frostbite is characterized by anesthesia and erythema. Second-degree frostbite will have superficial vesicles surrounded by edema. Third-degree frostbite produces hemorrhagic vesicles. Fourth-degree injuries extend deeper into osseous and muscle tissue. Optimal treatment should begin with removing all wet or cold clothing and assessing the patient for possible hypothermia. Any parts that are frozen should be submerged in warm circulating water (37°C - 39°C). Warming should not be initiated until it is certain that refreezing will not occur as this can cause more tissue damage. Passive rewarming with warm blankets (D) will not adequately increase the temperature to prevent further damage. Placing the frozen extremity in hot water (B) is often too painful for the patient to tolerate and may produce added heat injury. Application of dry heat (C) is also contraindicated as it leads to further damage and is poorly tolerated.
A 35-year-old Caucasian woman presents with complaints of dark brown patches of skin on her upper lip and forehead. She first noticed the lesions last year while she was pregnant but it has persisted. What is the most important intervention to reduce worsening of this skin manifestation? Camouflaging agents Exfoliating agents Photoprotection Topical corticosteroids
Correct Answer ( C ) Explanation: Photoprotection is the most important intervention in reducing melasma. Melasma often presents during pregnancy and is characterized by light- to dark-brown patches of skin on the face. It is sometimes called "the mask of pregnancy". This is often secondary to hormonal changes and can occur in women taking oral contraceptives as well. The macular, hyperpigmented areas are either found on the forehead, cheeks, and upper lip area, the mandibular area, or in a malar distribution. Melasma can be divided into four clinical types: epidermal type, dermal type, mixed type, and indeterminate type. A Wood's lamp can be used to distinguish between the types.
24-year-old man presents for evaluation of a rash. The patient reports a mildly pruritic rash on his back and trunk that progressively spread over the last week. You examine and note the rash seen above. Which of the following historical elements is most likely to be obtained upon further questioning? A larger 2 to 5 cm erythematous patch preceded the diffuse rash Fever preceded the onset of rash Oral mucosal lesions preceded the onset of rash Travel to the Southeast USA occurred a week before the rash
Correct Answer ( A ) Explanation: This patient has pityriasis rosea. This is a mild skin eruption that is self-limited usually lasting 4 to 7 weeks. There is no clear etiology of the rash although infection with Herpesvirus 7 or a fungus is suspected. Prior to the onset of the diffuse rash, patients may recall a herald patch described as a 2 to 5 cm erythematous oval plaque similar to the smaller more diffuse lesions. The rash is described as following a "Christmas tree" pattern on the trunk, classically following the skin cleavage lines. There is no indicated treatment for pityriasis rosea other than antihistamines for symptomatic relief if the rash is pruritic. A history of travel to the Southeast USA (D) before the onset of rash should raise an index of suspicion for an infectious etiology to the rash like Rocky Mountain Spotted fever, a tick-borne illness caused by Rickettsia rickettsii. This illness occurs most commonly in late spring and early summer and is characterized by a rash that starts distally and spreads to the core.
A 24-year-old man presents to the ED with a rash on his left flank. He is an avid hiker in the upper Midwest. He was bit by a tick two weeks ago. What would you expect to find on physical examination? AAnnular erythematous patch with central clearing BDiffuse erythroderma over the trunk and extremities CMaculopapular rash over the trunk following Langer's lines DPetechiae involving the palms and soles before spreading centrally
Correct Answer ( A ) Explanation: This patient is exhibiting risk factors for and signs of Lyme disease. Lyme disease is the most common vector-borne disease in the United States. It is endemic to New England, the mid-Atlantic states, and the upper Midwest. It is caused by the spirochete Borrelia burgdorferi and transmitted by the Ixodes dammini tick, more commonly known as the deer tick. The tick must be attached for more than 48 hours for transmission to occur. There are three stages of clinical Lyme disease. Early Lyme disease is characterized by erythema migrans, an annular erythematous patch with central clearing, which classically has a "bull's eye" appearance. Hematogenous spread leads to diffuse erythema migrans, which spares the palms and soles. Acute disseminated Lyme disease occurs approximately 4 weeks after initial infection and can include meningoencephalitis, Bell's palsy (which may be bilateral), or carditis which often manifests with AV block. Late Lyme disease develops greater than 1 year after initial infection and includes chronic arthritis with or without chronic subtle encephalopathy. Only 50% of patients remember a tick bite; thus, diagnosis may be difficult. Erythema migrans is diagnostic; however, not all patients present with this finding. Initial screening involves ELISA testing with Western Blot and PCR to confirm the diagnosis. If the diagnosis is suspected, empiric treatment should be administered. Treatment for early Lyme disease and mild acute disseminated Lyme disease is doxycycline. In pregnant women or children under the age of 8 years, amoxicillin should be substituted. Patients with neurologic or cardiac manifestations should be admitted and treated with IV ceftriaxone.
A 3-year-old boy presents to the Emergency Department for decreased appetite and fever. Vital signs are BP 88/50 mm Hg, HR 110 beats per minute, RR 18 breaths per minute, and T 101.9°F. On physical exam, you note the lesions seen above. Which of the following is the most likely causative agent? Coxsackievirus A Parvovirus B19 Rickettsia rickettsii Treponema pallidum
Correct Answer ( A ) Explanation: This patient is exhibiting signs and symptoms consistent with hand-foot-and-mouth disease. Hand-foot-and-mouth disease is a viral illness most often affecting children under the age of 5 years. It is classically caused by the coxsackievirus A. Coxsackieviruses belongs to the Enterovirus family. Coxsackieviruses are transmitted primarily through direct or droplet contact from nasopharyngeal secretions. Signs and symptoms include fever, oral ulcers and vesicles on the buccal mucosa and tongue, and a peripherally distributed, tender maculopapular rash that includes the palms of the hands and soles of the feet. Hand-foot-and-mouth disease is a self-limited illness. Management is primarily supportive and includes antipyretics for fever, oral rehydration, and analgesia with over-the-counter medications including acetaminophen. Oral rehydration may prove difficult with oral ulcerations and topical oral anesthetics may prove useful in aiding this endeavor.
A 33-year-old woman presents to her primary care provider for a pruritic rash on her wrists. She denies new exposures. On physical exam, multiple papules are present on the anterior wrist. The papules are flat-topped, 2-3 mm in diameter, and purple in color. On close inspection, there are fine, white lines on the surface of the papules. Which of the following is the most likely diagnosis? Lichen planus Lichen sclerosus Lichen simplex chronicus Lichen striatus
Correct Answer ( A ) Explanation: This woman most likely has lichen planus. Lichen planus is an uncommon disorder that can affect the skin, oral cavity, genitalia, scalp, nails, or esophagus. Lichen planus most commonly affects middle-aged adults. There are no known sex or racial predilection for lichen planus. Lichen planus is thought to be caused by CD8+ T cells directed against basal keratinocytes. Patients with hepatitis C have an increased prevalence of lichen planus compared to controls. Cutaneous lichen planus classically presents as flat-topped violaceous papules. These lesions are often described as the four "P's": pruritic, purple, polygonal, papules or plaques. On close examination of the lesions, fine white lines may be visible on the surface of the papules or plaques. These lines are termed Wickham's striae. The ankles and wrists are the most common sites for cutaneous involvement. Skin biopsy is useful for confirming the diagnosis. Topical corticosteroids are typical first-line therapy for localized cutaneous lichen planus. High potency or super high potency topical corticosteroids are used for trunk and extremity lesions. Mid-to-low potency topical corticosteroids are recommended for intertriginous or facial lesions. Second-line therapy includes oral corticosteroids, phototherapy, and oral acitretin. Cutaneous lichen planus is typically a self-limited condition. Lichen sclerosus (B) most commonly presents as pruritic, white, atrophic papules and plaques. The anogenital region is affected in the vast majority of lichen sclerosus cases, although any skin surface may be affected. Lichen simplex chronicus (C) is a thickening of skin caused by repeated scratching or rubbing. The skin lesion of lichen simplex chronicus is typically slightly erythematous, scaly, well-demarcated, firm, and rough. These lesions can appear anywhere the patient can reach. Lichen striatus (D) is an acquired, self-limited, asymptomatic linear skin disorder that most often involves the extremities. Lichen striatus predominantly affects children ages 5 to 15 years. Lichen striatus is characterized by red, pink or skin-colored flat-topped papules that follow the lines of Blaschko in a continuous or interrupted pattern.
Which of the following is true regarding the use of tissue adhesives for wound repair? Frequent prolonged exposure to water should be avoided to prevent premature breakdown of the tissue adhesive Standard wound care, including use of topical antibiotic ointment, should be performed on lacerations closed with tissue adhesives Tissue adhesives can be used to close lacerations on mucosal surfaces Tissue adhesives can be used to close lacerations that occur as a result of animal bites
Correct Answer ( A ) Explanation: Tissue adhesives can break down prematurely with frequent prolonged exposure to water. Therefore patients should be instructed to avoid soaking the affected area and activities such as swimming. Patients can shower and pat the area dry, however scrubbing and vigorous washing should be avoided. Tissue adhesives, or skin glues, are cyanoacrylates formulated for use on human skin. They are indicated for closure of linear, non-contaminated lacerations to the face, extremities and torso. Generally they are effective on wounds with little tension that would be amenable to repair with 5-0 sized suture material. Benefits of tissue adhesives include: ease and speed of application, minimal to no patient discomfort with application, reduction in needle-stick risk to healthcare providers, provides a protective covering to the wound and eliminate need for follow-up for suture removal. Cosmetic result is similar if not better than repair with sutures. Wound strength is initially less with skin glue closure, however after 7 days is comparable to sutured wounds. Tissue adhesive breaks down with in 5-10 days and the material will slough off without intervention.
A previously healthy 63-year-old woman presents to your office with a complaint of a painful rash that started two days ago. Physical exam shows a grouping of vesicles on an erythematous base just distal to the right scapula. There are no other skin lesions present. Which of the following is the most appropriate therapy? Acyclovir Amitriptyline Cephalexin Ganciclovir
Correct Answer ( A ) Explanation: Varicella-zoster virus (VZV) is the virus responsible for chickenpox and herpes zoster, also called shingles. Chicken pox is the initial infection that occurs after exposure to the virus. Herpes zoster occurs when the dormant virus is reactivated. Herpes zoster can occur at any age, but is more common in individuals older than 50 years. Clinical presentation of herpes zoster is a painful, unilateral, vesicular rash that occurs in a dermatomal distribution. In patients who are immunocompetent, the vesicles crust in 7-10 days and are no longer considered to be contagious at that point. Diagnosis is determined based on clinical presentation. Treatment decisions are based on duration of symptoms, clinical presentation, patient's age and immune state. Immunocompetent patients older than age 50 years who present within 72 hours of the onset of symptoms should be treated with an antiviral medication such as acyclovir (or valacyclovir) to help decrease symptoms and duration of the infection. The herpes zoster vaccine is recommended for individuals aged 60 years and older to help prevent herpes zoster infection.
A 34-year-old woman presents to the emergency room with a puncture wound over the second metacarpophalangeal joint of her right hand. She was playing with her friend's cat when it bit her. Which of the following is the most appropriate treatment for this patient? Amoxicllin Amoxicllin-clavulanate Cephalexin Clindamycin
Correct Answer ( B ) Explanation: Amoxicillin-clavulanate is the first line antibiotic for patients with a human, cat, or dog bite. This patient has suffered an animal bite injury. Bite wounds can be complicated by osteomyelitis, septic arthritis, and tenosynovitis; therefore, prophylactic antibiotics are appropriate. Amoxicillin-clavulanate provides essential coverage against Pasteurella multocida, commonly found in the mouths of cats and dogs. In patients with a penicillin allergy, choose an antibiotic with coverage against P. multocida (such as TMP-SMX or doxycycline) paired with anaerobic coverage (clindamycin or metronidazole). Appropriate treatment consists of immediate, copious irrigation, assessment for risk of tetanus and rabies, and administration of prophylactic antibiotics as discussed above.
Which of the following describes a burn that causes pressure and discomfort, extends into the dermis, and may have thick-walled blisters or be leathery white? First-degree burn Second-degree deep partial thickness burn Second-degree superficial partial thickness burn Third-degree burn
Correct Answer ( B ) Explanation: Burn classification is based on burn depth. Second-degree burns are classified into superficial and deep partial-thickness burns. Deep partial-thickness burns extend into the reticular dermis. Skin color is usually a mixture of red and blanched white, and capillary refill is slow. Blisters are thick-walled and commonly ruptured and the skin may appear leathery white. Two-point discrimination may be diminished, but pressure and pinprick applied to the burned skin can be felt. Superficial partial-thickness burns usually re-epithelialize 7-10 days after injury, so the risk of hypertrophic scarring is very small. For deep partial-thickness burns, tissue may undergo spontaneous epithelialization from the few viable epithelial appendages at this deepest layer of dermis and heal within 3-6 weeks. Because these burns have less capacity for re-epithelializing, a greater potential for hypertrophic scar formation exists. In deep partial-thickness burns, treatment with topical antimicrobial dressings is necessary to prevent infection as the burn wound heals. Contraction across joints, with resulting limitation in range of motion, is a common sequela. Splash scalds often cause second-degree burns. First-degree burns (A) involve only the epidermis and are erythematous and painful, without blisters. They are usually described as looking like a sunburn. These are not considered in the calculation of total body surface area when calculating burn size. Second-degree superficial partial-thickness burns (C) are erythematous and have thin-walled fluid-filled blisters. These usually heal in 2 to 3 weeks without scarring. Third-degree burns (D) involve all layers of the dermis. The skin is firm, white, or charred and often described as leathery. This represents complete tissue destruction, and surgery is necessary except in the smallest of third-degree burns. Fourth-degree burns extend to deeper tissues, including subcutaneous fat, muscle, and bone. Significant debridement and reconstruction are required.
A 3-year-old girl is brought to her pediatrician's office for a rash on her face and arms. Many children in the girl's school have similar rashes. On exam, she is well-appearing. The lesions on her face are shown above. Similar lesions are also noted on the posterior surface of both of her hands. Which of the following is the most appropriate treatment? Intravenous penicillin G Oral cephalexin Oral doxycycline Topical mupirocin
Correct Answer ( B ) Explanation: Children with widespread impetigo should be managed with systemic antibiotics, like oral cephalexin. Impetigo is common pediatric bacterial skin infection that is highly contagious and autoinoculable. Impetigo is commonly caused by Staphylococcus aureus and Group A beta-hemolytic Streptococci. Impetigo is most commonly seen in children ages 2-5 years. Risk factors for impetigo include warm, humid conditions, poverty, crowding, and poor hygiene. Secondary impetigo can occur at sites of minor abrasion or scratches. Impetigo typically begins as papules that progress to vesicles and surrounding erythema. Over about one week, the vesicles eventually rupture and form a thick, adherent, golden crust. Regional lymphadenopathy is a common finding. Gram stain and culture is recommended to determine bacterial etiology. However, empiric antibiotics are typically initiated based on clinical presentations. Small, localized areas of impetigo can be treated with topical antibiotics. More extensive involvement usually requires systemic therapy. Beta-lactamase resistant antibiotics with staphylococcal and streptococcal coverage are typically used. Impetigo outbreaks are treated with oral antibiotics. Patients with suspected or confirmed methicillin-resistant S. aureus should be treated with doxycycline, clindamycin, or trimethoprim-sulfamethoxazole. Antibiotic treatment is usually for seven days. Children may return to school 24 hours after starting antibiotics. Topical mupirocin (D) is inadequate in this child with numerous impetigo lesions. Topical mupirocin is indicated for infections limited to a small area due to compliance and cost.
A 24-year-old woman presents complaining of "bumps" in her genital area for the past several weeks that seem to be getting larger. She is sexually active. Physical exam reveals small, non-tender, flesh-colored, papillary growths on the vulva as shown. What is the most likely diagnosis? AAcrochordon BCondyloma acuminata CMolluscum contagiosum DSebaceous cys
Correct Answer ( B ) Explanation: Condyloma acuminata, or genital warts, are caused by an infection with the human papilloma virus (HPV). Mainly types 6 and 11 present in this manner. It is a sexually transmitted infection (STI) that can be prevented with vaccination. Symptoms include white to flesh-colored, exophytic or papillomatous growths in the genital area. In women, this can affect the vagina, cervix, vulva, oropharynx, perineum, and perianal areas. HPV can be spread via sexual contact or from mother to newborn during passage through the birth canal. Treatment includes trichloroacetic acid solution, podophyllin, cryosurgery, surgical excision, or imiquimod cream application. Acrochordon (A) is a flesh-colored growth commonly known as a skin tag.
A sexually active 17-year-old woman presents to her primary care clinic complaining of the lesions seen above around her genital area. Which of the following is the cause of these genital lesions? Herpes simplex virus Human papillomavirus Poxvirus Treponema pallidum
Correct Answer ( B ) Explanation: Condyloma acuminatum are the most common form of viral genital mucosal lesions and are caused by several types of human papillomavirus (HPV). The majority of genital warts are caused by HPV strands 6 and 11. The infection manifests as painless, verrucous fleshy papules. The warts may be located anywhere in the anogenital area. Lesions usually appear within weeks to months after exposure to HPV. They are generally asymptomatic, but may be painful, friable, or pruritic.
A 33-year-old woman with a history of Celiac disease presents with a chronic, pruritic papulovesicular lesions occurring symmetrically over the extensor surfaces of her elbows and knees. Several vesicles have a crusted appearance. Which of the following is the most likely diagnosis? Atopic dermatitis Dermatitis herpetiformis Erythema nodosum Pyoderma gangrenosum
Correct Answer ( B ) Explanation: Dermatitis herpetiformis an intensely pruritic papulovesicular rash, is pathognomonic for Celiac disease. It most commonly occurs at the extensor surfaces of the elbows and knees as well as buttocks, and may occur even in patients who appear to have no gastrointestinal problems. Diagnosis of dermatitis herpetiformis is made by visualizing granular IgA deposition on immunofluorescence of a skin biopsy. As with the gastrointestinal manifestations of Celiac disease, dermatitis herpetiformis typically resolves with full elimination of gluten from the diet. Atopic dermatitis (A) in adults usually presents with dry, pruritic areas of inflammation at the elbow and knees flexor surfaces. It is associated with underlying allergic conditions like asthma and allergic rhinitis. Erythema nodosum (C) is characterized by painful, red nodules commonly in a pretibial distribution, which fade into bruises after approximately 2 weeks. It is seen in with systemic illnesses including sarcoidosis and inflammatory bowel diseases as well as after using certain antibiotics and contraceptives. Pyoderma gangrenosum (D) typically presents as an inflamed papule or pustule that progresses to a painful ulcer with a violaceous, purulent base; it is associated with underlying autoimmune conditions including inflammatory bowel disease.
A 32-year-old man presents to the office with a rash on both of his hands. The rash appeared a couple days after completing yard work. He wore gloves while working and reports no similar rashes in household contacts. There are pink patches with multiple tapioca-like vesicles involving primarily the palms and web spaces on both hands. Which of the following is the most likely diagnosis? Contact dermatitis Dyshidrotic eczematous dermatitis Rhus dermatitis Scabies
Correct Answer ( B ) Explanation: Dyshidrotic eczema is an intensely pruritic, chronic recurrent dermatitis, typically involving the palms and soles. It starts as an episode of intense itching, followed by the formation of small vesicles. The vesicles are described as tapioca-like on the lateral aspect of the fingers and show confluence. Desquamation occurs over 1-2 weeks, leaving fissures and erosions. Treatment includes a high-potency topical steroid and prevention of secondary infection. Rhus dermatitis (C), also known as toxicodendron dermatitis, is a specific type of contact dermatitis to oil produced by plants in the genus Toxicodendron (poison ivy, poison oak and poison sumac) among others.
An 18-year-old woman presents with a laceration to her face from a dog bite that occurred 10 hours ago. The patient owns the dog. Examination reveals a 4 cm laceration to the left cheek with no signs of infection. What is the most likely management that is indicated? Irrigation and antibiotics Irrigation and primary wound closure Primary wound closure after irrigation and antibiotics Primary wound closure and antibiotics
Correct Answer ( B ) Explanation: Mammal bites to any part of the body should be copiously irrigated and explored followed by an assessment for primary closure. In this patient, primary closure is recommended as the laceration is on the face. Canine bites often involve laceration as well as crush injury to tissue depending on the size of dog. The presence of a crush injury may make primary wound repair difficult. Additionally, devascularization of the tissue may make primary closure contraindicated as the risk of infection increases. Classically, it was taught that lacerations sustained from dog bites should be irrigated, given antibiotics and not primarily repaired because of these risks. However, more recent literature has shown that the risk of infection was no different for primary closure versus healing by secondary intention. Additionally, if the laceration is to a cosmetic area like the face, primary repair should be attempted. As with any laceration, tetanus status should be updated. Copious irrigation and wound exploration is central to good wound care. Exploration should pay particular attention to the presence of foreign bodies especially teeth, which may break off during the bite.
Which of the following lesion characteristics is most concerning for melanoma? 5 mm in size Color variation Smooth borders Symmetry in shape
Correct Answer ( B ) Explanation: Melanoma accounts for < 1% of total skin cancers, but is responsible for the majority of deaths attributed to skin cancer. Basal cell cancer and squamous cell cancer are the two most common types of skin cancer. Melanoma is the result of malignant transformation of melanocytes and is caused primarily by ultraviolet exposure from the sun. The characteristics of melanoma include asymmetry, border irregularity, color variation (especially red, white, or blue tones in a black or brown lesion), diameter > 6 mm and a lesion that is evolving in appearance over time. Referral for excisional biopsy is indicated if any suspicious characteristics are present. Early recognition and treatment is key. Five year survival for stage 0 melanoma is 97%, but decreases to less than 20% in stage IV disease.
A previously healthy 6-year-old girl presents to your office with a complaint of an itchy scalp. She has been scratching her head and neck constantly and has not slept well due to severe itching. Physical exam reveals excoriations on the head and neck and white nits attached to the hair shafts. Which of the following is the most appropriate treatment? Lindane Permethrin Petroleum jelly Trimethoprim-sulfamethoxazole
Correct Answer ( B ) Explanation: Pediculosis capitis is a condition caused by infestation of the scalp and hair by the head louse, Pediculus humanus capitis. Also referred to as lice or lice infestation, pediculosis capitis is very common worldwide and most frequently affects children. Lice are parasites that live on the human body and feed on human blood. The injection of saliva after biting causes an allergic reaction with resulting pruritus. Lice spread through person-to-person contact or through contact with fomites (e.g. brushes or clothing). Diagnosis is through physical exam revealing the presence of nits, immature lice, or adult lice. First-line treatment is with topical pediculicides, such as permethrin. A second treatment should be applied on day nine after the first treatment to ensure eradication. Topical lindane (A) is a pediculicide that is not recommended in the treatment of lice due to resistance and safety concerns including rare neurologic side effects
A 15-year-old boy comes to clinic with a two week history of multiple round and oval lesions on his back and abdomen. The rash started as a single oval lesion on his back and then spread over the next few days. The rash is slightly pruritic. He is afebrile with symmetric distribution of oval to round, slightly raised pink lesions with collarette scales at the periphery as shown above. His exam is otherwise unremarkable. Which of the following is the most likely diagnosis? Lichen planus Pityriasis rosea Psoriasis Seborrheic dermatitis
Correct Answer ( B ) Explanation: Pityriasis rosea is a benign viral disease which usually starts with a herald patch, a solitary round or oval lesion that may occur anywhere on the body, measuring from 1 to 10 cm in diameter. Approximately five to ten days after the appearance of the herald patch, a generalized and symmetric eruption becomes evident involving the upper extremities and the trunk. The lesions are characterized as oval or round, slightly raised, pink to brown in color, covered by fine scale on the edges or collarette scales, measuring less than 1 cm in diameter. The rash typically follows a Christmas tree pattern on the back, lasts up to 2 to 12 weeks, and can be pruritic. Treatment includes topical emollients and oral antihistamines. On some occasions, topical corticosteroid ointment may be necessary to alleviate pruritus.
A 12-year-old girl presents with a rash. Erythematous papules and plaques are noted over her back. A prominent, oval-shaped, scaling papule is present on her right upper back. What is the most likely diagnosis? Atopic dermatitis Pityriasis rosea Tinea corporis Tinea versicolor
Correct Answer ( B ) Explanation: Pityriasis rosea is a classic childhood exanthem. The rash begins with the appearance of a characteristic herald patch, an erythematous, oval-shaped, sharply demarcated lesion that is most common on the upper back, chest, or neck. The rash subsequently spreads down the trunk in a "Christmas-tree" distribution along the cleavage lines of the skin. In children, it may also affect the face, scalp, and extremities. The lesions may desquamate and result in post-inflammatory hyperpigmentation. Many children may be asymptomatic, while others may experience intense pruritus. The typical course of pityriasis rosea is self-resolution, which may take weeks to months. Some patients may require topical steroids to control itching.
A 34-year-old woman with a history of chronic hepatitis C presents to her primary care provider complaining of pruritic skin discolorations on her feet. Physical exam is notable for multiple, violaceous, angulated papules on her feet. Close examination reveals fine, white lines overlying the lesions. Which of the following is the most appropriate management of this condition? Oral prednisone Topical betamethasone Topical clotrimazole Topical mupiroci
Correct Answer ( B ) Explanation: The first-line treatment for cutaneous lichen planus is topical corticosteroids, like topical betamethasone. Lichen planus is a mucocutaneous disorder that primarily affects middle-aged adults. Men and women are equally affected. The etiology of lichen planus is thought to involve activated T cells directed against basal keratinocytes. An association is noted between hepatitis C virus and lichen planus. Lichen planus can involve the skin, mucous membranes, scalp, and nails. Cutaneous lichen planus classically presents with papulosquamous eruptions that are described by the four P's: pruritic, purple, polygonal, and papules (or plaques). Fine, white lines (Wickham's striae) overlying the lesions may be noted upon close inspection. Lichen planus is most commonly located on the ankles and wrists. Lichen planus may exhibit the Koebner phenomenon (lesion development at site of trauma). Oral lichen planus manifests as painful ulcers. Skin biopsy may be required if diagnosis, based on clinical findings, is uncertain. Topical corticosteroids are typically the mainstay treatment for cutaneous lichen planus. High potency topical corticosteroids are recommended for the trunk and extremities, while mid-to-low potency topical corticosteroids are preferred for the face and intertriginous areas. Extensive disease may require short-term oral corticosteroids. Cutaneous lichen planus typically spontaneously resolves within 1-2 years.
A 27-year-old woman presents complaining of recurrent skin infections along her axilla since age 19. Prior incision and drainage coupled with short courses of antibiotics have resulted in temporary resolution of the skin lesions, only to have them recur again. Physical examination reveals an obese female with two 1 cm erythematous papules along the right axilla. The left axilla is notable for cord-like scarring and double blackheads, without any actively erythematous lesions. A culture obtained from one of the axillary lesions shows no bacterial growth. Which of the following is true about this condition? Effective management consists primarily of repeated incision and drainage Evidence supports an association between smoking and severity of disease Hormonal factors appear unrelated to disease severity and remission This condition is more common in men than women
Correct Answer ( B ) Explanation: This patient has hidradenitis suppurativa (HS), a chronic skin condition involving recurrent painful, erythematous nodules, occurring most commonly in the axilla and groin that results from occlusion of follicles and secondary inflammation of the apocrine glands. Lesions may also occur along the perineum, perianal region, abdomen and breasts. The lesions may exhibit purulence, and can lead to chronic scarring and the development of sinus tracts. The cause of HS is unclear; theories include an abnormal immune response of the skin may play a role. Smoking has been found to worsen disease severity and frequency of recurrence. Treatment is challenging, with topical antibiotics, antiandrogens, and oral antibiotics being the mainstay of therapy. Isotretinoin and surgical excision are all used, typically with limited results.
An eight-year-old previously healthy boy presents with concern for a pruritic rash. Examination of the right arm reveals an erythematous, circular, scaly plaque with slight central clearing. What is the treatment of choice? Griseofulvin Terbinafine Topical clotrimazole Topical nystatin
Correct Answer ( C ) Explanation: The above child has classic findings of tinea corporis, a dermatophyte infection that occurs in both immunocompromised and immunocompetent hosts. The rash begins as an erythematous, raised, scaly patch or plaque that enlarges centrifugally. The borders may become slightly more raised than the rest of the rash, and the center clears. While the diagnosis may be clinically apparent, KOH preparation of skin scrapings may be used to confirm the diagnosis. Topical azoles such as topical clotrimazole, are first-line therapy for tinea corporis. Topical nystatin (D) provide excellent treatment for cutaneous candidal infections but is ineffective against dermatophytes.
A 54-year-old woman presents to the ED with a painful rash. She experienced severe mouth sores and pain with swallowing for the past week and then developed this rash. Physical exam is shown above. Nikolsky sign is positive. Which of the following conditions is commonly associated with this disease process? Idiopathic thrombocytopenic purpura Myasthenia gravis Sarcoidosis Wegener's granulomatosis
Correct Answer ( B ) Explanation: This patient is exhibiting symptoms and physical exam findings consistent with pemphigus vulgaris. Pemphigus vulgaris is a potentially life-threatening autoimmune mucocutaneous intraepithelial bullous disease. It has a higher prevalence in Jewish and Mediterranean populations. It is often associated with myasthenia gravis and thymoma. Pemphigus vulgaris is caused by IgG autoantibodies against keratinocytes and their desmosomes that causes acantholysis, or loss of cell-to-cell adhesion. Signs and symptoms include early mucous membrane lesions preceding skin lesions, most commonly oral and esophageal involvement leading to dysphagia, hoarse voice, and dehydration, and the classic bullous rash. The bullae are painful, flaccid, and easily rupture. Patients have a positive Nikolsky sign as well as a positive Asboe-Hansen sign, where gentle lateral pressure on the bullae spreads the fluid into neighboring unaffected skin. Diagnosis is by skin biopsy to differentiate pemphigus vulgaris from Stevens-Johnson syndrome or bullous pemphigoid. Treatment is with steroids and immunomodulators such as azathioprine, cyclosporine, or methotrexate. These patients should be admitted as there is a high mortality rate without treatment. Mortality even with treatment remains as high as 5-15%.
A 55-year-old man presents with right sided chest pain and a rash for 4 days as seen above. What management should be initiated? Diphenhydramnine Pain control Topical antibiotics Topical corticosteroids
Correct Answer ( B ) Explanation: This patient presents with herpes zoster (shingles) and should have appropriate pain control started. Herpes zoster results from the reactivation of dormant variclla zoster virus developing in patients with a history of chickenpox. Typically, pain in a dermatomal distribution precedes the eruption of grouped vesicles on an erythematous base in the same dermatome. The vesicles are cloudy at first and progress to crust formation later in the course. The pain associated with the disease is often severe and debilitating. Patients may have chronic post-herpetic neuralgia as well. The mainstay of treatment is control of pain to make the patient comfortable. Orally administered corticosteroids are commonly used in the treatment of herpes zoster, even though clinical trials have shown variable results. Prednisone used in conjunction with acyclovir has been shown to reduce the pain associated with herpes zoster
A 12-year-old boy is brought to the emergency department by his parents after he was bitten by a stray cat while playing on the neighborhood playground. The patient reports moderate pain of the right hand and wrist but has full range of motion and strength. Which of the following is the next best step in the management of this patient? Admit patient to monitor for rabies symptoms; administer post-exposure prophylaxis if they arise Irrigate wound, leave open to drain, and prescribe amoxicillin-clavulanate prophylaxis Obtain radiographs of the right hand Wound irrigation with primary closure and antibiotic prophylaxis
Correct Answer ( B ) Explanation: This patient's bite wound should be left open to drain and heal by secondary intention due to the increased risk of infection associated with cat bites and bites involving the hand. He should also receive antibiotic prophylaxis. Although many animal bite wounds can be sufficiently treated through irrigation and primary closure, there are several criteria that increase the risk of infection of a wound and thereby necessitate healing by secondary intention and administration of antibiotic prophylaxis. The factors that increase the risk of infection include: venous/lymphatic compromise, involvement of the hand, location near a prosthetic joint, cat bites, crush injuries, deep puncture wounds, delayed presentation, or an immunocompromised host. Bite wounds should be irrigated with normal saline, and the wound should be further evaluated for potential tendon/bone involvement or foreign bodies. Amoxicillin-clavulanate is the first-line antibiotic prophylactic agent used for animal bites. Post-exposure rabies prophylaxis should be considered in every animal bite and administered where appropriate. State laws often require physicians to report cases of animal bites. Staphylococcus, Streptococcus, and anaerobes are common to all bites. Pasteurella species are seen in dog and cat bites, and Eikenella species are associated with human bites. Bite wounds with a higher risk of infection should be left to heal by secondary intention with the wound left open to drain under close observation; in this case, a cat bite, a bite involving the hand, and delayed presentation all confer an increased risk of infection.
A 72-year-old woman complains for discolored toenails that have been present for years and has spread toward the cuticles from the distal corners. She tries to wear well fitting shoes and keeps her nails trimmed. On physical exam, the nail of the great toe is yellow-brown in color and appears thickened. The proximal end of the nail appears normal. Which of the following is the most likely diagnosis? Onychogryphosis Onychomycosis Subungual hematoma Tinea pedis
Correct Answer ( B ) Explanation: This woman most likely has onychomycosis. Onychomycosis is fungal infection of the nail. Onychomycosis can be caused by fungi, yeasts, and nondermatophyte molds. Fingernail onychomycosis is most commonly caused by yeast. Onychomycosis is more common in adults than in children and is more common in men than in females. There are several subtypes of onychomycosis, but the most common clinical subtype is distal lateral subungual onychomycosis. Over 80% of onychomycosis cases in the United States are caused by Trichophyton rubrum. Risk factors for onychomycosis include increased age, swimming, tinea pedis, psoriasis, diabetes, immunodeficiency, and living with individuals with onychomycosis. Distal lateral subungual onychomycosis often begins on the great toe spreading from a distal corner to the cuticle. The nail appears yellowish or brownish and is often thickened and rough. Although onychomycosis is primarily a cosmetic concern for most patients, occasionally severe disease can cause discomfort or pain. The diagnosis of onychomycosis can be confirmed with either a KOH preparation or periodic-acid-Schiff staining. Treatment of onychomycosis is recommended in the following populations: patients with a history of lower extremity cellulitis, patients with diabetes and cellulitis risk factors, immunosuppressed patients, and patients with cosmetic concerns. Treatment primarily consists of topical and systemic antifungal drugs. Systemic therapy has a higher cure rate and shorter treatment courses but may be inappropriate in certain patients.
This above rash has been present for 36 hours. What is the most likely cause of the lesions? Acute rheumatic fever Drug reaction Herpes simplex virus Lyme disease Syphilis
Correct Answer ( C ) Explanation: This patient has erythema multiforme, an acute immune-mediated self-limited rash characterized by target-shaped skin lesions. The most common known causes include reactivated herpes simplex, Mycoplasma pneumonia, and upper respiratory tract infections. Rarely, it can be associated with allergens, drugs, connective tissue diseases, and internal malignancies. While it can present with multiple forms, such as red macules and papules, urticarial-like lesions, vesicles and bullae, most of these will evolve over 24-48 hours to form 1-3 cm target lesions. Diagnosis is based on this classic clinical appearance, with a central lesion surrounded by a pale area of edematous skin and a surrounding sharp discrete ring of erythema. Lesions appear in crops, resolve in two to four weeks, and often involve the palms and soles. Involvement of oral mucosa differentiates erythema multiforme major from erythema multiforme minor. Treatment involves symptomatic treatment and topical steroids, systemic steroids with taper for severe disease or mucosal involvement, and antiviral suppressive therapy for recurrent lesions associated with herpes. This evanescent feature differentiates them from the fixed lesions of erythema multiforme. Drug reaction (B) is a less common cause of erythema multiforme than herpes simplex.
A 26-year-old woman presents with the chief complaint of intensely itchy hands and fingers. Your exam reveals multiple clear vesicle at the palms and sides of her fingers with a tapioca-grain appearance. Unroofing the vesicles and performing a KOH preparation does not reveal hyphae. In addition to a topical corticosteroid, which of the following pieces of patient education should be given to this patient? Adhere to strict avoidance of gluten Avoid prolonged exposure of the hands to water Limit use of moisturizers as much as tolerated Use prescription-strength high-SPF lotion with UVA/UVB coverage on the hands daily
Correct Answer ( B ) Explanation: Vesiculobullous hand eczema, or dyshidrosis, should be managed with topical corticosteroids for acute flares and by avoidance of long exposure of the hands to water. Dyshidrosis is a very common form of hand dermatitis that usually presents in adults with a history of atopy and persists for life. On exam, patients will have vesicles of 1-2 mm on their soles, palms and sides of the fingers that appear to contain "grains of tapioca." Intense pruritus is common. As flares subside, patients will be left with scaling and fissuring over the affected area. A diagnosis of dyshidrosis requires ruling out other causes of hand dermatitis, and should include a KOH preparation of unroofed vesicles to rule out bullous tinea or inflammatory tinea pedis when the feet are affected. Topical corticosteroids often bring dramatic improvement in dyshidrosis during acute vesicle eruptions as well as for the fissuring that usually follows resolution of the vesicles. Patient education to wear cotton-lined vinyl gloves when working in water and to consistently apply moisturizers after washing hands is imperative in the management of this disease.
A 30-year-old daycare worker has a 3-day history of arthralgias, malaise, and a rash. The rash is nonpruritic, maculopapular, irregular, and is located on her thighs and inner aspects of her upper arms. Symmetric synovitis is present in her fingers. Small effusions, warmth, and tenderness are noted in her left wrist and right elbow. No other joints are affected. Which of the following is most likely responsible for this presentation? AAdenovirus BMeasles (rubeola) virus CParvovirus B19 DVaricella-zoster virus
Correct Answer ( C ) Explanation: Also known as erythema infectiosum or Fifth disease, parvovirus B19 infection usually is asymptomatic or causes mild, nonspecific, cold-like symptoms. However, several clinical conditions have been linked to the virus. Parvovirus B19 usually infects children and causes the classic "slapped-cheek" rash of erythema infectiosum (fifth disease). The virus may also cause acute or persistent arthralgias and papular, purpuric eruptions on the hands and feet in adults. This infection should be particularly suspected in health-care workers who have frequent contact with children. Parvovirus B19 infection can also trigger an acute cessation of red blood cell production, causing transient aplastic crisis, chronic red cell aplasia, hydrops fetalis, or congenital anemia.
A 32-year old woman and her 2 children present to your office with a 4-day history of intense itching that is worse at night. They specifically complain of pruritus under their arms and in between their fingers and toes. They deny any changes in household cleaners, new carpets or any allergies to pets. On physical exam you notice small papules and vesicles on the extremities and the axilla. You also notice burrows in between the fingers and toes. Skin scrapings confirm your suspected diagnosis. Which of the following is the first-line treatment for this disease? Corticosteroid cream Malathion lotion Permethrin cream Topical mupirocin
Correct Answer ( C ) Explanation: Based on the history and physical exam, this patient and her children most likely have scabies. Human scabies is an intensely pruritic skin infestation caused by the host-specific mite Sarcoptes scabiei hominis. Bite distribution and intractable pruritus that is worse at night, as well as scabies symptoms in close household contacts should immediately rank scabies at the top of the clinical differential diagnosis. Small papules, vesicles and burrows in the webbed spaces of the fingers and toes, axilla, elbow and belt line are the classical distribution of scabies lesions. The treatment of choice for primary scabies infection is the application of topical scabicidal agents, with repeat application in 7 days. The treatment of choice is permethrin 5% lotion. Individuals affected by scabies should avoid skin-to-skin contact with others. Patients with typical scabies may return to school or work 24 hours after the first treatment.
One of the mainstay treatments for patients diagnosed with systemic lupus erythematosus is an antimalarial drug hydroxychloroquine. Prior to starting a patient on this medication, which of the following baseline screening tests or exams is recommended? Assessment of bone mineral density Mammogram Ophthalmologic exam Papanicolaou test (Pap test)
Correct Answer ( C ) Explanation: Early diagnosis and treatment of systemic lupus erythematosus (SLE) is important in preventing tissue and organ damage, achieving remission, and ensuring long-term survival. An antimalarial drug, hydroxychloroquine, is the mainstay of treatment for patients with lupus. Hydroxychloroquine reduces lupus symptoms, reduces mortality, decreases incidence of diabetes, and has antithrombotic and favorable lipid effects. Hydroxychloroquine has high tolerability compared with corticosteroids.The long-term use of hydroxychloroquine may lead to retinal toxicity, which is why a baseline ophthalmologic examination is recommended when patients start hydroxychloroquine and every 6 - 12 months while taking this medication.
A 60-year-old man with a history of diabetes presents to your office with a complaint of thickened and discolored toenails. He tells you that his toenails have had this appearance for over a year, and now he is experiencing discomfort when wearing tight-fitting shoes. Physical exam reveals hyperkeratosis and onycholysis of bilateral great and second toes. Which of the following is the most appropriate next step in management? Begin treatment with oral terbinafine Check serum aminotransferases Potassium hydroxide examination of toenail scrapings Watchful waiting
Correct Answer ( C ) Explanation: Onychomycosis is a fungal infection of the toenails or fingernails that can involve any part of the nail including the plate, bed or matrix. There are several subtypes of onychomycosis, with the most common being distal subungual onychomycosis. This type presents with the great toe being the first affected. A white, yellow or brown discoloration can be seen that eventually spreads to the entire nail. Onycholysis, the separation of the nail from the plate, may also be seen. Onychomycosis is initially a cosmetic concern, however with time it can cause pain, disfigurement, and decreased quality of life. Other nail dystrophies can present similarly to onychomycosis, therefore establishing the presence of a fungal etiology is recommended prior to initiation of treatment. Diagnosis is with potassium hydroxide (KOH) examination of nail scrapings. Patients who are immunocompromised or who have diabetes mellitus are at an increased risk of bacterial infections due to onychomycosis. Treatment should be considered in these patients to avoid sequelae. Once a fungal etiology has been determined, first-line treatment is with oral antimycotic agents such as terbinafine (A). Terbinafine can cause hepatotoxicity, so pretreatment serum aminotransferases (B) should be measured prior to initiating therapy and then monitored during the course of treatment.
A 30-year-old man presents to his primary care provider's office for a rash. He has a past medical history of recurrent genital herpes. On physical exam, there are numerous target-like erythematous lesions involving the face, arms, hands, and trunk as shown above. Which of the following is the most likely diagnosis? Erythema infectiosum Erythema migrans Erythema multiforme Erythema nodosum
Correct Answer ( C ) Explanation: The man in this case most likely has erythema multiforme. Erythema multiforme (EM) is an immune-mediated, acute disorder characterized by target-like lesions of the skin. EM can be divided into EM major and EM minor based upon mucosal involvement. The majority of EM cases are caused by herpes simplex virus (HSV). Other causes include medications, malignancy, autoimmune disease, immunizations, radiation, and menstruation. Development of EM secondary to HSV is believed to involve an immune reaction against viral antigens deposited in the skin. Target-like lesions are the defining features of EM. The typical lesion is made up of a dusky center surrounded by a pale ring of edema and a red inflammatory zone. These lesions are typically distributed symmetrically and spread from the extremities to the trunk. Most cutaneous lesions are asymptomatic. EM major can involve the oral, ocular, or genital mucosa. Lesions typically appear over 3-5 days and resolve in 2 weeks. The diagnosis of EM is based on history and clinical findings. Laboratory findings are not required and are nonspecific. Biopsy may be required in questionable cases. The majority of patients with EM can be managed symptomatically with topical corticosteroids, oral antihistamines, and anesthetic mouthwash. Severe mucosal involvement may necessitate systemic corticosteroid therapy. Antivirals are not indicated in acute HSV-induced EM. Continuous antiviral therapy may be required for patients with recurrent EM.
A 35-year-old man presents to the ED with a severe rash. A localized portion is seen in the image above. He states that he was cleaning away some brush from the woods behind his house a couple of days ago while only wearing shorts. On exam, you note similar lesions on his face, back, legs, arms, and chest. Which of the following is the most appropriate treatment? Cephalexin for 7 days Diphenhydramine as needed Prednisone taper over 21 days Prednisone taper over 7 days
Correct Answer ( C ) Explanation: The patient was exposed to poison ivy and developed allergic contact dermatitis. Contact dermatitis is an inflammatory reaction of the skin to a chemical, physical, or biologic agent. The inducing agent acts as an irritant or allergic sensitizer. Clothing, jewelry, soaps, cosmetics, plants, and medications contain allergens that commonly cause allergic contact dermatitis. The most common allergens include rubber compounds, plants of the Toxicodendron genus (poison ivy, poison oak, sumac), nickel (often found in jewelry), paraphenylenediamine (an ingredient in hair dyes and industrial chemicals), and ethylenediamine (a stabilizer in topical medications). Clinical presentation is variable with primary lesions being papules, vesicles, or bullae on an erythematous base. The distribution of the eruption depends on the specific allergen and may be localized, asymmetric linear, or unilateral. The classic lesion of poison ivy is a linear eruption that occurs from the person brushing against the poison ivy leaf. The rash usually appears 2-21 days after exposure and is associated with intense pruritus. Treatment for mild cases of contact dermatitis from poison ivy includes calamine lotion or a topical steroid and oral antihistamine. However, in moderate to severe cases, systemic steroids are indicated and should be continued for 2-3 weeks, with a gradual taper to prevent rebound of the disease. Systemic antihistamines can be taken concomitantly to help control the pruritus.
A 23-year-old woman presents to her primary care provider complaining of a recurring rash on her hands. The rash erupted suddenly and is extremely pruritic. She denies any new exposures. Physical exam reveals multiple, deep-seated vesicles scattered on both palms symmetrically. Which of the following is the most likely diagnosis? Bullous pemphigoid Contact dermatitis Dyshidrotic eczema Herpetic whitlow
Correct Answer ( C ) Explanation: The woman in this case most likely has dyshidrotic eczema. Dyshidrotic eczema, also known as dyshidrosis or pompholyx, is dermatologic disorder characterized by intensely pruritic, vesicular eruptions on the palms or soles. Dyshidrotic eczema is most commonly seen in young adults. Recurrent episodes are common. Risk factors include a history of atopic dermatitis, exposures to allergens or irritants, intravenous immune globulin, smoking, and exposure to ultraviolet radiation. Dyshidrotic eczema episodes typically begin with pruritus, followed by acute eruption of extremely pruritic vesicles. The vesicles are usually deep-seated and often described as having a "tapioca pudding" appearance. In the majority of patients with dyshidrotic eczema, only the hands are involved. Vesicles last 2-3 weeks and then recur weeks to months later. Some patients report flares associated with emotional or physical stress. The diagnosis of dyshidrotic eczema is typically based on history and clinical findings alone; skin biopsy is rarely required. Treatment for mild to moderate disease involves high potency, topical corticosteroids that are applied two times per day for 2-4 weeks. Severe disease usually requires oral corticosteroids. Avoiding skin irritants and harsh soaps and applying emollients is an essential element of treatment. Recurrent episodes are less frequent with increasing age.
A 24-year-old man presents with a painful sore on his lower back that has been gradually enlarging and at times there is drainage. He has no other significant past medical history. He is afebrile and nontoxic appearing. Physical exam reveals a tender, erythematous, fluctuant mass in the midline sacrococcygeal region. Which of the following is the most likely diagnosis? Anal fistula Perirectal abscess Pilonidal abscess Pyoderma gangrenosum
Correct Answer ( C ) Explanation: This man most likely has pilonidal abscess. A pilonidal cyst is a not a true cyst due to lack of fully epithelialized lining. Pilonidal cysts are acquired rather than congenital. Risk factors for pilonidal cysts include obesity, local trauma and irritation, sedentary lifestyle, deep natal cleft, and family history. Pilonidal disease is thought to arise from an embedded hair, which creates a local cavity and sinus tract. The cavity may become infected and spontaneously drain through a sinus. Patients with symptomatic pilonidal disease typically complain of mild to severe pain in the intergluteal region while sitting. Patients may also report occasional swelling and drainage. Physical exam findings of pilonidal disease are one or more midline pores in the natal cleft. A sinus opening and tracts may be seen lateral to the primary pore. Pilonidal disease is based on physical exam and laboratory studies are not required. Management of acute pilonidal abscess includes incision and drainage at the time of presentation. Antibiotics are unnecessary unless cellulitis is present. Definitive treatment of pilonidal disease is surgical excision of all sinus tracts. Pyoderma gangrenosum (D) is an uncommon, ulcerative condition that is commonly associated with systemic diseases such as inflammatory bowel disease. Pyoderma gangrenosum appears as a deep ulceration with a violaceous border. Pyoderma gangrenosum lesions most commonly appear on the legs.
A 46-year-old woman presents to her primary care provider with a complaint of severe itching on her hands and fingers. On physical examination, linear vesicles and pustules with some excoriation are seen in the web spaces of the fingers. Which of the following will confirm the suspected diagnosis? Gram stain and culture Patch testing Skin scraping and microscopy Wood's lamp and KOH prep
Correct Answer ( C ) Explanation: This patient has Scabies, which is caused by an infestation with Sarcoptes scabiei. It is usually spread by being in close contact with an infected individual. The classic symptom of scabies is generalized, severe pruritus, particularly at night. Burrows, vesicles and pustule particularly in the finger web and wrist crease are hallmark physical findings. Definitive diagnosis is made by visualization of mites, ova, or feces under microscopy.
A 58-year-old man with diabetes mellitus and hypertension presents with a 6-month history of generalized pruritus. He reports that he scratches frequently. On examination his skin is dry and scaly. He has multiple linear excoriations and thickened skin on his forearms, legs, and neck. Which one of the following is the most likely cause of his pruritus? Chronic urticaria Contact dermatitis Lichen simplex chronicus Scabies
Correct Answer ( C ) Explanation: This patient has lichen simplex chronicus, consisting of lichenified plaques and excoriations that result from excessive scratching. On physical exam, one or more slightly erythematous, scaly, well-demarcated, lichenified, firm, rough plaques with exaggerated skin lines are noted. Atopic dermatitis results in a higher probability of developing lichen simplex chronicus. Psychological factors appear to play a role in the development or exacerbation of lichen simplex chronicus. Anxiety has been reported to be more prevalent in patients with lichen simplex chronicus. Insect bites, scars, postherpetic zoster, xerosis, venous insufficiency and asteatotic eczema are common factors. An elevated serum immunoglobulin E level occasionally supports the diagnosis of an underlying atopic diathesis. Perform potassium hydroxide examination and fungal cultures to exclude tinea cruris or candidiasis in patients with genital lichen simplex chronicus. Treatment is aimed at reducing pruritus and minimizing existing lesions because rubbing and scratching cause lichen simplex chronicus. Location, lesion morphology, and extent of the lesions influence treatment. For example, a thick psoriasiform plaque of lichen simplex chronicus on a limb is commonly treated with a highly potent topical corticosteroid or intralesional corticosteroids, whereas vulvar lesions are more commonly treated with a mild topical corticosteroid or a topical calcineurin inhibitor. Widespread lesions are more likely to require systemic treatment or total body phototherapy.
A 32-year-old woman presents complaining of "bumps" in her vaginal area that she noticed two weeks ago. She has never had these in the past. She denies any pain. Physical exam reveals several flesh colored lesions with prominent papillae that are non-tender to palpation on the labia as shown below. Which of the following is the next best step in management? Referral to general surgery for excision Application of trichloroacetic acid Perform colposcopy with acetic acid application Perform shave biopsy for confirmation
Correct Answer ( C ) Explanation: This patient is suffering from condyloma acuminatum, or genital warts, caused by an infection with the human papilloma virus (HPV), commonly types 6 and 11. Performing a colposcopy with acetic acid application will ensure that there is no infection of the cervix with condyloma acuminatum. This is important because human papilloma virus (HPV) infection is strongly associated with the development of genitourinary and rectal cancer. HPV is a sexually transmitted infection that can be prevented with vaccination. All girls and boys who are 11 or 12 years old should get the recommended series of HPV vaccine regardless of sexual history. Symptoms include flesh colored to whitish, exophytic or papillomatous growths in the genital area. In women, this can affect the vagina, cervix, vulva, oropharynx, perineum, and perianal areas. HPV can be spread via sexual contact or from mother to newborn during passage through the birth canal. Treatment includes trichloroacetic acid solution, podophyllin, cryosurgery, surgical excision, or imiquimod cream application.
A 60-year-old woman presents to her primary care provider complaining of a red rash that has developed on her cheeks and nose over the past few years. She states that occasionally the affected area becomes redder and feels like it is stinging or burning especially after drinking coffee. What is the preferred pharmacological treatment? 2.5% hydrocortisone Griseofulvin Metronidazole Mycophenolate mofetil
Correct Answer ( C ) Explanation: This patient likely has rosacea given her physical exam findings and symptoms. While there are many potential treatments, topical metronidazole cream is a first line agent. Rosacea is a very common cause of a red appearing face in Caucasians and people of Mediterranean descent. It most often develops between the ages of 30 and 50, although females tend to present earlier than males. While there are many subtypes of rosacea, there are management techniques that are common among the various types. Patients should avoid items that are known triggers. This often includes spicy foods, alcohol, emotional stress, and hot beverages. Numerous topical therapies may also be effective. Several topical metronidazole preparations may be used, and are significantly more effective in the papulopustular subtype of rosacea. There are four main classifications, which include erythematotelangiectatic rosacea, papulopustular rosacea, phymatous rosacea, and ocular rosacea. In addition to metronidazole, they discuss additional treatments for the various subtypes. Azelaic acid, oral tetracyclines, and vascular laser therapy may also be considered for erythematotelangiectatic and papulopustular rosacea. Oral tetracyclines are the initial therapies for the last two subtypes.
A 17-year-old man with asthma presents with an itchy, scaly rash on his arms and legs. He states that he has had the rash on and off for years. He states that the itching is severe and keeps him up at night. Physical examination reveals hyperpigmented areas to the antecubital and popliteal fossae which are thick and leathery. What management is indicated? Antibiotic ointment Cephalexin Corticosteroid ointment Oral steroids
Correct Answer ( C ) Explanation: This patient presents with an exacerbation of atopic dermatitis (AD) requiring topical corticosteroid treatment. AD is a common dermatologic condition. It is often referred to as eczema or chronic dermatitis. Patients with AD have abnormal humoral and cell-mediated immunity but the exact mechanism of the disease is unknown. AD has no pathognomonic skin lesions but does have a set of diagnostic criteria. These criteria include a history of involvement of flexor surfaces, generalized dry skin, history of asthma or hay fever, onset of rash before 2 years of age and flexor surface dermatitis. The presence of three or more of these is 85% sensitive and 96% specific for AD. AD is a chronic disease that waxes and wanes and is often worse in the winter. In general, treatment for AD is directed at controlling inflammation, dryness and itching. When patients present with acute symptoms, topical corticosteroid ointments can provide symptomatic relief. Antihistamines may be necessary as well. in addition, avoid scented products, wear light weight clothing, avoid hot baths, wash clothing in dye-free, unscented detergent.
A 78-year-old man presents to the ED with a concern about a bump on his head that has been present for several months, but has recently changed in appearance. The lesion is shown above. Which of the following is this patient at risk of developing? Basal cell carcinoma Kaposi sarcoma Malignant melanoma Squamous cell carcinoma
Correct Answer ( D ) Explanation: This patient has actinic keratoses, which are a precursor for squamous cell carcinoma. Squamous cell carcinoma is a malignancy of epidermal keratinocytes. It is usually caused by ultraviolet light exposure and those with fair skin are at highest risk. Other causes of squamous cell carcinoma include human papillomavirus (HPV) infection, arsenic exposure, and immunocompromised status. These lesions most commonly arise on sun-exposed areas, particularly the lip, ear, head, and neck. They appear as a well-defined red or brown thickened patch. Diagnosis is by biopsy, which will show malignant transformation of keratinocytes. Lesions > 2 cm in diameter and > 4 mm deep have a high risk of metastases. Treatment is with 5-fluorouracil ointment, cryosurgery, or full surgical excision.
A 65-year-old man with hypertension and diabetes presents with chest pain for 2 days. He states the pain is sharp, burning and severe. You note the findings on the image above. What management is indicated? Admission for serial troponins Intravenous acyclovir for 7 days Oral acyclovir for 7 days Prednisone for 5 days
Correct Answer ( C ) Explanation: This patient presents with herpes zoster more commonly referred to as shingles. Zoster results from reactivation of latent varicella-zoster virus (VZV) in cranial nerve or dorsal-root ganglia with spread along the sensory nerve to the dermatome. The major risk factor for herpes zoster is increasing age as there is a decline in T-cell immunity. Although herpes zoster can progress to a systemic infection, particularly in those with immunocompromised states, the major complication is postherpetic neuralgia. Postherpetic neuralgia can be severe and debilitating. Antiviral therapy (usually with acyclovir or valacyclovir) is recommended in all immunocompromised patients and selected groups of nonimmunocompromised patients. Antiviral agents hasten the resolution of lesions, reduce the formation of new lesions, reduce viral shedding and decrease the severity of acute pain. Therapy should be started as soon as possible and efficacy decreases after 72 hours of symptoms.
A 27-year-old man presents with a rash associated with mild pruritus. The rash is seen above. What treatment is indicated? Bacitracin Cephalexin Clotrimazole cream Oral ketoconazole
Correct Answer ( C ) Explanation: This patient presents with tinea corporis (ring worm), which responds to treatment with a topical antifungal agent. Tinea corporis is commonly caused by Trichophyton rubrum. Transmission occurs by person-to-person contact. The typical rash is a sharply marginated, annular lesion with raised edges and central clearing. The edges may be vesicular as well. Patients may present with single or multiple lesions affecting the arms, legs and trunk. Tinea cruris is the name applied to infections in the groin. Diagnosis is made on clinical presentation but can be confirmed by performing a KOH preparation of scrapings of the lesion. Infections usually respond to topical antifungal agents alone including clotrimazole, haloprogin, tolnaftate and miconazole. Treatment consists of two to three daily applications for 2 to 3 weeks.
34-year-old woman presents with a rash on her back for 3 months. She states that the rash gets worse in the summer. The patient's back is seen above. Which of the following managements is most likely indicated? Cephalexin for 7 days Permethrin topical Selenium sulfide topical Topical corticosteroids
Correct Answer ( C ) Explanation: This patient presents with tinea versicolor requiring treatment with selenium sulfide topical. Tinea versicolor is a superficial fungal infection caused by Malassezia furfur (formerly Pityrosporum ovale). Typically, patients will present with scaly patches on the chest and trunk but occasionally, the rash will spread to the limbs. There may be mild pruritus associated with the rash. Patients often seek care after sun exposure because the affected areas do not tan and will appear hypopigmented. The diagnosis is made based on clinical presentation but can be confirmed by a KOH preparation of scraping of the patches. The treatment for tinea versicolor is with 2.5% selenium sulfide shampoo, imidazole cream or oral fluconazole. Recurrence is common (15-50%).
A 30-year-old woman presents with a skin lesion on her left forearm. She has a past medical history of atopic dermatitis and hypertension. While talking to the woman, she absent-mindedly scratches at the lesion. Physical exam is notable for a slightly erythematous, scaly, well-demarcated plaque with surrounding excoriations. The plaque is approximately 4 cm by 5 cm on the extensor surface of the left forearm. Removing a scale does not cause bleeding. Which of the following is the most likely diagnosis? Lichen planus Lichen sclerosus Lichen simplex chronicus Plaque psoriasis
Correct Answer ( C ) Explanation: This woman most likely has lichen simplex chronicus. Lichen simplex chronicus is a dermatologic disorder secondary to repetitive rubbing or scratching. Lichen simplex chronicus is more common in females and in Asians and African Americans. Lichen simplex chronicus has the highest prevalence rate in mid-to-late adulthood. Patients may have a history of chronic skin disorders such as atopic dermatitis or allergic contact dermatitis. The lesions can occur on any location that the patient can reach, some of the most common locations include the extensor forearms and elbow, knees, nape of neck, vulva and scrotum, and scalp. Lichen simplex chronicus appears as one or more slightly erythematous, scaly plaques that are rough with well-defined borders. Scratch marks may be present. The diagnosis of lichen simplex chronicus is based on clinical findings. Skin biopsy may be required in cases in which the diagnosis is uncertain. Treatment involves breaking the scratch-itch cycle. Topical corticosteroids are the first-line pharmacologic treatment. Occlusive dressings can be used to increase delivery of the corticosteroid and to prevent further scratching. Oral anxiolytics may be required in some patients. Plaque psoriasis (D) presents with raised, inflamed plaques and papules with silvery scales. Pinpoint bleeding after removal of a scale from a psoriatic plaque (Auspitz sign) is a common clinical finding of plaque psoriasis. Many patients with psoriasis have a positive family history of the disorder.
A three-year-old boy weighing 15 kg requires repair of a laceration to his forearm. What is the maximum amount of 1% lidocaine without epinephrine that can be used for analgesia during the repair? 10.5 ml 3.75 ml 7.5 ml 8 ml
Correct Answer ( C ) Explanation: Wound anesthesia is an important consideration prior to beginning laceration repair on children. Lidocaine, an amide anesthetic, is an excellent agent capable of providing local anesthesia during laceration repair, foreign body removal, abscess management, and line insertion. There are multiple forms and concentrations of lidocaine. The maximum weight based dose of lidocaine without epinephrine is 5 mg/kg. The maximum dose of lidocaine with epinephrine is 7 mg/kg. This higher toxic dose is due to the vasoconstriction caused by epinephrine, which leads to less systemic absorption of lidocaine. Lidocaine toxicity affects the CNS, cardiovascular, and hematologic systems. For a patient that weighs 15 kg, the maximum dose of 1% lidocaine is is 75 mg (5 mg x 15 kg = 75 mg). Because the question asked for the amount, not the dose, it is necessary to know how many mg/mL are present in a given solution. A 1% solution of lidocaine has 10 mg/mL. Therefore, 75 mg (maximum dose) / 10 mg/mL = 7.5 mL. So 7.5 mL of 1% lidocaine is the maximum amount that can be used for anesthesia in this patient. If a 1% lidocaine with epinephrine solution is used, the amount of volume that can safely be administered is 10.5 mL (7 mg x 15 kg / 10 mg/mL = 10.5 mL). 3.75 mL (B) would be the correct maximum dose for a clinician using a 2% lidocaine solution.
A 66-year-old woman presents with a rash to the right side of her forehead that began 2 days ago. She describes it as painful, blistering, and weeping. On exam, you note the rash seen above. Which of the following is the most likely diagnosis Acne rosacea Contact dermatitis Herpes zoster Impetigo
Correct Answer ( C ) Explanation: Zoster ophthalmicus is due to reactivation of latent varicella virus in the dorsal root ganglia. It is characterized by a painful rash described as papulovesicular eruptions on an erythematous base along a dermatome. The lesions are often preceded by pain in a dermatomal distribution 2-3 days before the characteristic rash appears. Lesions often involve the face, mouth, eyes, ears, or tongue when branches of the trigeminal nerve are affected. Involvement of the tip of the nose is referred to as Hutchinson's sign and often signals concurrent ocular involvement of the nasociliary branch. Ramsey-Hunt Syndrome refers to involvement of the external auditory canal and development of an ipsilateral facial palsy. Treatment of zoster ophthalmicus involves analgesics, anti-inflammatories, and anti-viral medications (acyclovir or valacyclovir). The most common complication secondary to herpes zoster is post-herpetic neuralgia (chronic pain) of in the area of the involved dermatome.
Which of the following is the most common infection associated with erythema multiforme? Borrelia burgdorferi Haemophilus influenzae Type b Hepatitis C virus Herpes simplex virus
Correct Answer ( D ) Explanation: Although numerous infections have been reported in association with erythema multiforme (EM), herpes simplex virus (HSV) is the most common and best documented. Recurrent EM also is associated with infection with HSV. Demonstration of prior exposure to HSV by serology and documentation of a cutaneous recurrence of HSV infection was noted in a series of patients with recurrent EM and was less common in patients with a single episode. The pathogenesis of EM is incompletely understood, but evidence increasingly implicates a host-specific, cell-mediated immune response to an antigenic stimulus that targets keratinocytes at the dermal-epidermal junction. EM has variable cutaneous manifestations. EM is characterized by the acute onset of a symmetric, fixed cutaneous eruption of erythematous macules, papules, vesicles, or bullae most commonly distributed on the palms, dorsal surfaces of the hands and feet, and extensor surfaces of the arms and legs with relative sparing of the face, trunk and mucous membranes. Lesions can expand and evolve over several days to assume the classic annular "target" appearance with a dusky, necrotic center surrounded by a ring of edema and pallor and an erythematous border.
A 35-year old woman presents to your office with a 1-week history of high fevers, severe headaches and muscle pain. She also reports a rash. She denies any recent travel or changes in her diet. She is current on her immunizations. She currently lives in North Carolina and enjoys hiking in the outdoors. On physical exam her temperature is 102.3°F and she has a maculopapular rash on her extremities, including her hands and feet and sparing her face. She states the rash began a few days after her fever started and has progressively worsened. You decide to draw laboratory tests and titers in order to confirm the suspected disease. You also prescribe antibiotics immediately. Which of the following is most likely etiology of the disease? ABabesiosis BEhrlichiosis CLyme disease DRocky Mountain spotted fever
Correct Answer ( D ) Explanation: Based on the history and presentation, this patient most likely has Rocky Mountain Spotted Fever (RMSF) which is a tick-borne disease caused by the organism Rickettsia rickettsia. The organism is endemic in parts of North, Central, and South America, especially in the southeastern and south-central United States, such as North Carolina. History of hiking in the outdoors increases the likelihood even though there is no specific history of a tick bite. RMSF should be considered in patients with unexplained febrile illness even if they have no history of a tick bite or travel to an endemic area. The classic clinical triad of fever, headache, and rash should raise a high suspicion for RMSF, especially high fevers over 102°F. The rash begins as a maculopapular eruption on the wrists and ankles and spreads centripetally to involve the trunk and extremities. The face is usually spared. After exposure to vector ticks, patients who develop fever, petechial rash, and vomiting require antibiotic therapy. Antibiotic therapy should be initiated before laboratory confirmation is available. Doxycycline is the antibiotic of choice for RMSF. Doxycycline therapy also treats Lyme disease, ehrlichiosis, and relapsing fever; diseases often clinically confused with RMSF. Doxycycline should be initiated immediately in this patient. Babesiosis (A) is a tick borne illness that presents with Influenza-like symptoms, fever, sweating, myalgia, headache, hemolytic anemia, hemoglobinuria, jaundice, renal failure. Ehrlichiosis (B) is a tick-borne illness that presents with influenza-like syndrome, fever, chills, cough, malaise, headache, and myalgias. A rash is rare in this disease, differentiating this from RMSF.
A 16-year-old girl presents with a large "patch" on her skin that appeared about a week after adopting a stray cat. Physical exam reveals a well-demarcated scaling plaque with central clearing on her right forearm as shown above. What is the best exam to confirm this diagnosis? Biopsy Nitrazine test Polymerase chain reaction Potassium hydroxide preparation
Correct Answer ( D ) Explanation: Dermatophytes are fungi that infect the nonviable keratinized cutaneous structures such as stratum corneum, nails, and hair. There are three genera of dermatophytes: epidermomycosis which infects the skin, trichomycosis which infects hair and hair follicles, and onychomycosis which infects nails. Dermatophyte infections can be further differentiated by their location on the body. Tinea unguium refers to infections of the nails, tinea capitis is an infection of hair, and tinea corporis refers to an infection on the skin. These infections are usually transmitted from person to person, but other times may be passed on from animals (such as a stray cat), and less frequently from soil. Topical treatment consists of imidazoles and allylamines, while systemic treatments consist of terbinafine, imidazoles, itraconazole, fluconazole, ketoconazole, and griseofulvin. Clinical presentation may vary depending on the location of the infection, but tinea corporis is classically described as well-demarcated scaling plaques with central clearing, while tinea capitis often causes bald patches. Diagnosis can be made with the aid of a Wood's lamp which will cause the Microsporum species to fluoresce green. Typically though, diagnosis is made on direct microscopy of a sample in a potassium hydroxide (KOH) preparation.
A 55-year-old woman presents to the emergency room with a bright red, painful, well-demarcated rash on her face as seen above. Which of the following organisms is most likely responsible for this condition? Haemophilus influenzae Staphylococcus aureus Streptococcus pneumoniae Streptococcus pyogenes
Correct Answer ( D ) Explanation: Erysipelas is a cutaneous infection characterized by marked superficial dermal lymphatic involvement. The most common cause of erysipelas worldwide is Streptococcus pyogenes (group A beta-hemolytic Streptococcus). Facial erysipelas is frequently associated with streptococcal pharyngitis. Another common location for this infection is the lower legs. Additional risk factors include breaks in the skin barrier, venous disease, immunosuppression, and previous episodes of erysipelas or cellulitis. Clinical manifestations include raised, bright salmon-red colored lesions above the level of the surrounding skin with a clear line of demarcation between involved and uninvolved skin. Plaques may develop vesicles or bullae. In facial erysipelas, one or both eyes are frequently swollen shut. Fever, chills, headache, vomiting, and joint pain may precede the rash. Diagnosis is made by history and clinical presentation. Diagnostic tests may show an elevated white blood cell count, raised C-reactive protein, and positive blood cultures. Early diagnosis and treatment has an excellent prognosis. Empiric antibiotic therapy should be started immediately. First-line treatment is an oral penicillin such as amoxicillin. For patients with systemic symptoms, intravenous ceftriaxone or cefazolin is indicated. . Erythromycin can also be used but is associated with increasing resistance. Additional management includes analgesics, elevation of the involved area, compression stockings, and proper wound care. Complications are rare but may include abscess, thrombophlebitis, lymphatic damage, recurrent infection, infective endocarditis, septic arthritis, scarlet fever, post-streptococcal glomerulonephritis, cavernous sinus thrombosis, and toxic shock syndrome. Skin changes may take weeks to resolve but generally do not involve scarring.
A 55-year-old woman presents with fever, malaise and a facial rash. Physical exam reveals a temperature of 102.1°F, heart rate 115 bpm, and blood pressure 110/68 mmHg. There is a 5 x 6 cm area of deep erythema with induration and sharply demarcated borders involving the right cheek area. Which of the following pathogens is most frequently implicated in this patient's diagnosis? Haemophilus influenzae Staphylococcus epidermidis Staphylococcus saprophyticus Streptococcus pyogenes
Correct Answer ( D ) Explanation: Erysipelas is a soft tissue skin infection characterized by deeply erythematous, indurated skin with sharply demarcated borders. It typically involves the upper dermis, superficial lymphatics and the superficial subcutaneous tissue. Patients are often very young or 50- to 60-year olds presenting with a prodrome of fever, chills and malaise followed by the eruption of cellulitic skin changes. Erysipelas is most often seen on the lower leg (90%) followed by the arm (5%) and the face (2.5%). Streptococcus pyogenes is the predominant pathogen in erysipelas. It is a group A beta-hemolytic streptococci also known to cause streptococcal pharyngitis, scarlet fever and rheumatic fever. Effective antibiotic choices include penicillins, cephalosporins or macrolides. Staphylococcus epidermidis (B) is a part of normal skin flora. It is often grown on cultures as a contaminant or associated with iatrogenic infections of indwelling catheters or surgical devices. Staphylococcus saprophyticus (C) is a common cause of urinary tract infections.
An 18-year-old obese woman presents to your office with a complaint of redness and pain in her right axilla. Physical exam reveals a solitary nodule, approximately 2 cm in size, with surrounding inflammation and erythema. She tells you that she's had similar "boils" in the past. Which of the following is the most likely diagnosis? Contact dermatitis Dermoid cyst Granuloma inguinale Hidradenitis suppurativa
Correct Answer ( D ) Explanation: Hidradenitis suppurativa (HS) is a chronic inflammatory skin condition that causes scarring, keloids, contractures and immobility. Originally believed to be caused by a defect in the apocrine glands, it may also be due to a defect in the follicular epithelium. HS begins in adolescence or adulthood in otherwise healthy individuals. Risk factors for the development of HS include obesity, genetics, smoking, diet and mechanical stress on the skin. Onset is insidious, with the first presentation generally being erythema in an intertriginous skin area, most commonly the axilla. As the disease progresses, formation of sinus tracts, multiple open comedomes and scarring occur. The initial presentation can mimic other disorders and individuals often are diagnosed incorrectly with recurrent furunculosis. Diagnosis is a clinical one. Treatment includes medical management in the early stages and surgical intervention after the formation of abscesses or sinus tracts.
You are about to repair a laceration on your patient when she tells you that she is allergic to lidocaine. Which of the following anesthetics is a suitable alternative? Bupivacaine Mepivacaine Prilocaine Procaine
Correct Answer ( D ) Explanation: Local anesthetics can be divided into two classes, the esters and the amides. The two most commonly used local anesthetics in the ED, lidocaine and bupivacaine, are amides. In a patient allergic to one class, a drug from the other class should be used. One way to remember which class each anesthetic belongs to is to use the following trick: all of the amides have two i's in their spelling, whereas the esters have only one i.
A previously healthy 25-year-old woman presents to your office with a complaint of a rash. The rash started as one 5 cm, round, salmon-colored lesion. One week later numerous smaller lesions appeared on her back and on her upper arms. The lesions are not painful, but are mildly itchy. Which of the following is the most appropriate therapy? Clobetasol propionate Clotrimazole Permethrin Triamcinolone acetonide
Correct Answer ( D ) Explanation: Pityriasis rosea is a common, benign skin rash most often seen in healthy individuals, children, and young adults. The cause is unknown, but thought to be viral in nature. The rash generally begins with a larger-sized pink or salmon-colored lesion on the back, followed by smaller, similar looking lesions approximately one to two weeks later that may spread to the proximal extremities. The lesions may be mildly pruritic and resolve spontaneously within two to three months. Diagnosis is a clinical one based on history and physical exam, but skin biopsy may be done if the diagnosis is in question. Treatment is to address pruritus and a low to medium potency topical corticosteroid (e.g. triamcinolone acetonide) is recommended as first-line therapy. Antihistamines can also be used. Clobetasol propionate (A) is a super high potency steroid and not recommended to treat pityriasis rosea
A 3-week-old term girl presents with a rash that has been present since birth. She is eating well, has regained her birth weight, and making normal wet and dirty diapers. She has had no fevers. There is no family history of asthma or eczema. Her parents are concerned because her rash has worsened over the last week. Your exam shows a well appearing, alert infant with vital signs within normal limits for age and the above rash. Which of the following is the most likely diagnosis? Acropustulosis of infancy Atopic dermatitis Erythema toxicum Seborrheic dermatitis
Correct Answer ( D ) Explanation: Salmon-covered greasy patches with yellow scale characterize seborrheic dermatitis (i.e. cradle cap) that occurs most commonly on the scalp but can include the diaper area and axillae as well. The rash seems more upsetting to the parents than the infants, as they otherwise are asymptomatic and healthy. The rash can appear severe, especially when it develops into dark red patches in the diaper area and trunk. It usually clears without treatment within 2-3 months but can last as long as 8-9 months. For seborrheic dermatitis of the scalp, removing dry flaky skin with a soft brush after using oil or petrolatum can improve the appearance and help with the anxiety of the parents. While conservative treatment is recommended, especially severe cases can be improved with topical corticosteroids or ketoconazole cream. Acropustulosis of infancy (A) is an uncommon, benign chronic and recurrent pustular rash on the palms and soles of infants although it can involve the scalp. The lesions however are pustular, not flaky, in appearance. Atopic dermatitis (B) can appear much like seborrheic dermatitis initially but usually has a waxing and waning course and family history of atopy. Erythema toxicum (C) is an extremely common benign rash with blotchy macules and papules usually clustered over the face, trunk, and proximal extremities that fade over 5-7 days but can recur for several weeks. It is "flea-bitten", not flaky, in appearance.
A five-month-old girl presents to your ED with a worsening rash. Her regular doctor diagnosed her with eczema three days ago and the parents are trying topical emollients without effect. She is fussy and having difficulty sleeping. She has had no fevers. No one in the family has a history of asthma or atopy, however her five-year-old brother recently developed a similar rash. Your exam shows a well appearing and well nourished infant trying to scratch at the above rash. Of the following, which is the most appropriate topical treatment? Hydrocortisone 1% Mupirocin 2% Nystatin 100,000 units/gram Permethrin 5% cream
Correct Answer ( D ) Explanation: Scabies is a highly contagious infestation of the mite Sarcoptes scabiei causing a common polymorphic intensely pruritic rash in children. The classic presentation is that of linear burrows in the webs of fingers and toes but this is rarely seen. The lesions can be subtle, small erythematous nondescript papules, vesicles, or nodules that are often excoriated and may be tipped by a hemorrhagic crust. The distribution of the lesions varies depending on the patient's age, likely representing the different areas with which the mite has contact. In adults the lesions are often seen in the axillae, nipples, wrists, elbows, waist, and the groin. In infants and toddlers the distribution includes the head, neck, trunk, axillae, palms, soles, and ankles. Treatment is with permethrin 5% cream. The entire family and everyone who comes in contact with the infant should be treated simultaneously. Bed linens and other fomites should be cleaned or placed in a plastic bag for one week to interrupt the life cycle of the parasite. Permethrin dries the skin so the use of emollients is recommended after treatment.
Which one of the following is associated with an erythematous rash and is caused by a bacterial infection? German measles Measles Roseola Scarlet fever
Correct Answer ( D ) Explanation: Scarlet fever is caused by Group A beta-hemolytic Streptococcus (GABS). The pathogenesis is due to erythrogenic toxins (A, B, and C) and occurs most frequently with pharyngitis. Scarlet fever is manifest with a characteristic sandpaper, confluent, erythematous rash, which is usually self-limited.
A 19-year-old is brought to the ED via ambulance after he was found sleeping outside in a snowstorm. The ambient temperature is 25°F. His vital signs are T 36.0°C, BP 125/70 mm Hg, RR 14, and HR 75. He complains of stinging and burning pain in all ten fingers. On exam, you note edema, erythema, and multiple blisters beginning to form over the fingers and hands. Which of the following is the most appropriate next step in management? Administer intravenous antibiotics Debridement of blisters Dry rewarming at 98.6°F (37°C) Wet rewarming at 98.6°F (37°C)
Correct Answer ( D ) Explanation: This patient has evidence of moderately severe (second-degree) frostbite. Rapid rewarming is the cornerstone of frostbite therapy and should be initiated as soon as possible. The injured extremity should be placed in gently circulating water (ideally a whirlpool) at a temperature of 98.6°F to 102.2°F (37°C to 39°C) for approximately 15 to 30 minutes until the distal extremity is pliable and erythematous.
Which of the following statements regarding allergic drug reactions is true? Celecoxib often causes a reaction in patients with a sulfonamide allergy Cross-reactivity between penicillins and first generation cephalosporins is 50% Patients with a history of anaphylaxis to penicillin can never be given penicillin The onset of serum sickness generally occurs within one to two weeks
Correct Answer ( D ) Explanation: Serum sickness (D) is an immune-complex mediated reaction characterized by malaise, joint pain, urticaria, fever, adenopathy, and hepatosplenomegaly. Symptoms usually begin one to two weeks after drug exposure and may take several weeks to resolve. Treatment is generally supportive with corticosteroids administered for more severe cases. The rate of cross-reactivity of penicillins and first generation cephalosporins is approximately 1%-7%, not 50% (B). Third and fourth generation cephalosporins have a much lower cross reactivity than first generation, closer to 1%. Patients with a history of penicillin anaphylaxis should not be given penicillin or cephalosporins, however, there are a few selected indications where desensitization (C) should be performed. An example is the pregnant patient with syphilis and a penicillin allergy. Careful desensitization should occur in the ICU with increasing doses of the medication.
A 50-year-old white man presents to clinic complaining of "a bump" on his face that he first noticed about a year ago. It has been slowly growing during this time, but due to his work as a fisherman, and has not had time off to have it evaluated. On physical exam you note a small, flesh-colored papule with central ulceration that bleeds easily on palpation. What is the most likely diagnosis? Actinic keratosis Basal cell carcinoma Malignant melanoma Squamous cell carcinoma
Correct Answer ( D ) Explanation: Squamous cell carcinoma is a common form of skin cancer that may arise on any part of the skin, though in fair-skinned individuals, it is more common on skin exposed areas, such as on the face of this patient. In darker skinned individuals, it may appear on the legs, anus, and areas of chronic inflammation or scarring. Treatment is often surgical, but chemotherapy may be necessary for metastatic disease. It is essential, therefore, to palpate for metastasis, particularly at the regional lymph nodes which are the most frequent sites for metastasis. A biopsy that extends to the mid-reticular dermis helps to establish a definitive diagnosis, since more superficial biopsies may not provide enough cells for adequate evaluation. It is possible, however, to establish a likely diagnosis during the physical exam. Squamous cell carcinoma often presents as a erythematous or flesh-colored papules or nodules with central erosions or ulcerations. Any tenderness, bleeding, or palpable underlying substance rises the suspicion of squamous cell carcinoma, making it the most likely diagnosis for this patient.
A 50-year-old man currently on a regimen of penicillin develops a diffuse rash and facial swelling. On physical exam there are diffuse dark reddish purple papular lesions on his trunk, face, and extremities with extensive blister formation. Prior to the onset of the rash the man complained of a nonproductive cough, fever, and chills. Based on his history and physical exam, what is the most likely diagnosis? Herpes zoster Impetigo Scabies Stevens-Johnson syndrome
Correct Answer ( D ) Explanation: Stevens-Johnson syndrome (SJS) is a hypersensitivity reaction of the skin and mucous membranes due to medication, malignancy, or a medical condition. Drugs and malignancy are most often implicated as the etiology in adults and the elderly whereas infections are more often the cause in children. It begins with non-specific upper respiratory infection symptoms and then progresses to dermal manifestations. The rash begins as painful macules and papules which progress to purpuric and vesicular lesions. They rupture and cause extensive sloughing. It can be life-threatening if not treated immediately and adequately with antibiotics, steroids, pain medications, and IV fluid hydration. Debridement and skin grafting may also be necessary.
An 11-year-old girl presents with an itchy lesion that has been present on her proximal left arm for one week. It began as a small, scaly red patch and has spread outward to form an erythematous circle with a whitish center. The bordering edges appear slightly more raised than the rest of the circle. What is the most likely diagnosis? Granuloma annulare Nummular eczema Pityriasis rosea Tinea corporis
Correct Answer ( D ) Explanation: The above child has classic findings of tinea corporis, a dermatophyte infection that occurs in both immunocompromised and immunocompetent hosts. The lesion begins as an erythematous, raised, scaly plaque that enlarges centrifugally. The borders may become more raised than the rest of the lesion, while the center begins to clear. As multiple lesions often occur in the same individual, examination of the entire body surface area is necessary. The diagnosis is often clinically apparent, but in uncertain cases, KOH preparation of skin scrapings may be used to visualize hyphae. First-line treatment of tinea corporis in an immunocompetent child is a topical azole antifungal.
A 14-year-old boy developed an erythematous, papular rash over his palms and fingers. A complete physical examination reveals scaling and cracking in the interdigital webs of his feet. No other areas are affected. What is the most appropriate treatment? Intramuscular benzathine penicillin G Permethrin cream applied from the neck down Supportive care for hand-foot-and-mouth disease Terbinafine cream applied twice daily to feet
Correct Answer ( D ) Explanation: The above patient presents with auto-eczematization, also known as an id reaction, which is thought to be due to a delayed-type hypersensitivity reaction to a fungal infection. In this case, it is secondary to his tinea pedis. Tinea pedis, also known as athlete's foot, is the most common dermatophytic fungal infection. Affected individuals develop vesicles or papules over the soles and interdigital webs of the feet, followed by scaling and cracking. It most commonly results in sterile vesicles over the palms and soles. The id reaction resolves with treatment of the primary infection. The treatment of choice for tinea pedis is a topical antifungal, such as terbinafine or clotrimazole, applied to the affected area for four weeks. The correct answer is terbinafine applied twice daily to feet.
A 17-year-old boy is in your clinic because of itchiness on both feet. He noted lesions on his feet for about two weeks that are accompanied by pruritus and pain. He denies any history of allergies or trauma. On physical examination, vital signs are normal. On skin examination, there are pruritic, erythematous erosions and scales in the interdigital areas of the toes of both feet. There are also some interdigital fissures seen. Which of the following is the most likely diagnosis? Erythrasma Interdigital Candida infection Palmoplantar psoriasis Tinea pedis
Correct Answer ( D ) Explanation: The boy has findings that are consistent with tinea pedis. Tinea pedis (also known as athlete's foot) is the most common dermatophyte infection. Tinea pedis may manifest as an interdigital, hyperkeratotic, or vesiculobullous eruption. Interdigital tinea pedis is most common. Tinea pedis usually occurs in adults and adolescents (particularly young men). Common causes are Trichophyton rubrum, Trichophyton interdigitale and Epidermophyton floccosum. Infection is usually acquired by means of direct contact with the causative organism, as may occur by walking barefoot in locker rooms or swimming pool facilities. The boy has interdigital tinea pedis that manifests as pruritic, erythematous erosions or scales between the toes, especially in the third and fourth digital interspaces. Associated interdigital fissures may cause pain. The diagnosis is confirmed with the detection of segmented hyphae in skin scrapings from an affected area with a potassium hydroxide (KOH) preparation.
A 16-year-old boy is in the clinic with his father for a sports physical examination. He participates in wrestling in school. He eats a healthy diet. Family history is negative for heart disease or sudden death in a relative younger than 50 years of age. He denies shortness of breath, chest pain, palpitations, or loss of consciousness. On physical examination, heart rate is 75 beats per minute, respiratory rate is 16 cycles per minute, temperature is 36.5 oC, body mass index is at the 87th percentile, clear breath sounds, no murmur, soft abdomen. On skin examination, there is an annular plaque with central clearing and a raised border measuring about 5 cm in diameter. There are fine scales present. Which of the following is the most likely diagnosis? Granuloma annulare Nummular eczema Subacute cutaneous lupus erythematosus Tinea corporis
Correct Answer ( D ) Explanation: The boy has skin examination findings consistent with tinea corporis. Tinea corporis is a cutaneous dermatophyte infection occurring in sites other than the feet, groin, face, or hand. Trichophyton rubrum is the most common cause of tinea corporis. Acquisition of infection may occur by direct skin contact with an infected individual or animal, contact with fomites, or from secondary spread from other sites of dermatophyte infection. Tinea corporis often begins as a pruritic, circular or oval, erythematous, scaling patch or plaque that spreads centrifugally. Central clearing follows, while an active, advancing, raised border remains. The result is an annular (ring-shaped) plaque from which the disease derives its common name. Multiple plaques may coalesce. Pustules occasionally appear. A potassium hydroxide (KOH) preparation will show the segmented hyphae characteristic of dermatophyte infections. The highest yield is obtained from skin scrapings taken from the active border of a plaque. A fungal culture is an alternative, albeit slower method for diagnosis. Granuloma annulare (A) is a benign inflammatory condition that classically presents with one or more erythematous or violaceous annular plaques on the extremities. Unlike tinea corporis, scale is absent. Nummular eczema (B) typically presents with highly pruritic, round, coin-shaped patches of eczematous dermatitis ranging in diameter from 1 to 10 cm. In the acute phase, lesions are dull red, exudative, and crusted. Over time, they become more dry and scaly, occasionally with central clearing leading to annular lesions. The legs and the upper extremities are the sites most frequently involved. Subacute cutaneous lupus erythematosus (C) can be idiopathic or occur in association with systemic lupus erythematosus or drug exposure. It often manifests as annular or polycyclic erythematous scaly plaques on sun-exposed skin.
A 17-year-old girl with no past medical history presents with pain and swelling to the left axilla for 3 days. She states this has never happened before. Physical examination reveals a 3 cm area of swelling and tenderness in the axilla with no warmth or erythema. The area is fluctuant. Which of the following represents the appropriate management? Amoxicillin and follow up Ciprofloxacin and follow up CT scan with contrast Incision and drainage
Correct Answer ( D ) Explanation: The patient presents with an uncomplicated, simple cutaneous abscess, which should be treated with incision and drainage (I&D). A simple cutaneous abscess is a localized collection of pus that results in a fluctuant soft tissue mass. They can occur in any part of the body but are most commonly found in the neck, axilla and perirectal areas. Most abscesses contain bacteria but up to 5% of them are sterile. This is most commonly seen in patients with parenteral drug abuse. The majority of cutaneous abscesses are caused by skin flora and Staphylococcus aureus is the most commonly cultured aerobic agent. Abscesses near mucous membranes (perioral and perirectal) tend to predominantly be caused by anaerobic bacteria. The standard treatment for cutaneous abscesses is incision and drainage. In patients with normal immune systems and minimal erythema after drainage, antibiotics are not indicated. For I&D, the incision should be made to adequate length and depth to ensure complete drainage. The cavity is typically left open with or without a wick for drainage.
A 54-year-old man presents to the ED complaining of back pain. He states that over the previous two days he developed a headache, cough, and runny nose. You perform a physical examination and note lesions as seen in the picture above. What is the cause of this skin condition? Herpes simplex virus Morbillivirus Roseolovirus Varicella-zoster virus Variola
Correct Answer ( D ) Explanation: The rash is consistent with shingles, which is due to reactivation of the latent varicella-zoster virus. This condition is most often seen in older individuals. The classic rash is dermatomal in distribution and is often described as grouped vesicles on an erythematous base. The lesions remain in congruent stages of healing as compared to chicken pox (varicella) that exhibits multiple stages of healing. Infection begins as a prodrome of headache, photophobia, malaise, and itching and burning in the affected area 1-3 days before the appearance of the rash.
A 34-year-old woman presents complaining of patches of pale skin that have progressively developed over the past several years. The patches are easily sunburned. Physical exam reveals numerous depigmented patches on her hands, elbows, knees, and around her eyes. Which of the following is the most likely diagnosis? Keloids Melasma Tinea versicolor Vitiligo
Correct Answer ( D ) Explanation: The woman in this case most likely has vitiligo. Vitiligo is an acquired dermatologic depigmentation disorder. Vitiligo is most frequently seen in persons 10-30 years of age. Approximately 20-30% of patients have a family history of vitiligo. Vitiligo is thought to be caused by autoimmune destruction of melanocytes. Patients with vitiligo have an increased frequency of other autoimmune conditions such as Hashimoto thyroiditis, Grave's disease, diabetes mellitus, pernicious anemia, and systemic lupus erythematosus. The most common presentation of vitiligo is generalized depigmented patches and macules. The lesions are chalk or milk white in color. Frequently affected areas are the acral skin, skin surrounding orifices, and extensor surfaces. The diagnosis of vitiligo is based on clinical findings. The Koebner phenomenon may be observed with increased macules around sites of trauma. Treatment for limited vitiligo consists primarily of topical corticosteroids. Other repigmentation therapies include calcineurin inhibitors, ultraviolet light, and surgery. Patients with vitiligo should be advised to use sunscreen to minimize tanning, which increases the contrast between diseased and normal skin. Makeups and skin stains may also be beneficial. The disease course of vitiligo is usually slow and spontaneous remission occurs in 10-20% of patients.
A 7-year-old boy presents to the Emergency Department with a rash. He has had a mild fever at home, but denies any respiratory symptoms. Vitals signs are BP 100/60 mm Hg, HR 90 beats per minute, RR 18 breaths per minute, and T 100.9°F. On physical exam, you note the above rash, as well as postauricular and suboccipital lymphadenopathy. With which of the following patient populations should this patient avoid contact due to the risk of severe complications? Elderly patients Newborn infants Oncology patients Pregnant women
Correct Answer ( D ) Explanation: This patient is exhibiting signs and symptoms consistent with rubella. Rubella is a viral illness characterized by a mild maculopapular rash, lymphadenopathy, and low-grade fever. The rash begins on the face, becomes generalized within 24 hours, and lasts a median of 3 days. Lymphadenopathy is characteristically posterior auricular and suboccipital in location. However, up to 50% of infections are asymptomatic. When rubella infection occurs during pregnancy, especially during the first trimester, serious consequences can result. These consequences include miscarriages, fetal deaths or stillbirths, and severe birth defects known as congenital rubella syndrome (CRS). The most common congenital defects associated with rubella are cataracts, heart defects, and hearing impairment. Thus, this patient should avoid contact with pregnant women. Rubella virus is an enveloped, positive-stranded RNA virus in the Togaviridae family. Rubella is transmitted primarily through direct or droplet contact from nasopharyngeal secretions. Humans are the only natural hosts for this virus. Rubella has become rare in the United States due to childhood immunization; however, it is increasing in incidence due to the decrease in children being immunized and occurs almost exclusively among unimmunized patients. The rash is difficult to distinguish from other conditions and so close attention must be paid to the accompanying exam and lack of other significant symptoms. You should consider rubella in unvaccinated patients with febrile rash, lymphadenopathy in characteristic locations, and lack of other viral symptoms, such as cough. Because rubella is difficult to accurately diagnose clinically, collection of throat swab specimens is advised for viral detection by PCR and blood for serologic testing.
A 43-year-old man presents with pain, swelling, and redness to his left leg for 2 days. He denies fever or history of similar presentations in the past. He was hospitalized a month ago for 3 days. Vital signs are unremarkable. Physical examination reveals a 3 cm area of erythema, warmth, and purulence on the left shin. What treatment is recommended? Amoxicillin-Clavulanate Cephalexin Ciprofloxacin Trimethoprim-Sulfamethoxazole (TMP-SMX)
Correct Answer ( D ) Explanation: This patient presents with signs and symptoms of cellulitis requiring antibiotic treatment covering the most likely pathogens. Cellulitis is a soft tissue infection involving the skin and subcutaneous tissue. It is characterized by erythema, swelling, local warmth and tenderness. Cellulitis can occur anywhere on the body but usually presents on the lower extremities, upper extremities and face. Staphylococcus aureus and Streptococcus pyogenes are the most commonly isolated organisms and antibiotics should be directed against these pathogens. The diagnosis is made clinically and there is no specific test that aides in diagnosis. Standard treatment is with immobilization, elevation, warm compresses and antibiotics. In the last 10-15 years, community acquired methicillin resistant S. aureus (CA-MRSA) has become a common causative organism. Cephalexin is a first generation cephalosporin with activity against many streptococcus and staphylococcus species but not against MRSA. TMP-SMX is active against most strains of MRSA but does not have adequate activity against S. pyogenes. Per IDSA guidelines, for outpatients with purulent cellulitis (e.g., cellulitis associated with purulent drainage or exudate in the absence of a drainable abscess), empirical therapy (e.g. TMP-SMX) for CA-MRSA is recommended pending culture results. Empirical therapy for infection due to β-hemolytic streptococci is likely to be unnecessary.
A 22-year-old gravida 1, para 0 woman presents to her obstetrician seeking advice on safe treatment of her acne. She has had acne for many years, but is not using any treatment currently due to her fears of potential pregnancy complications. Which of the following medications should this patient avoid? Oral erythromycin Topical azelaic acid Topical clindamycin Topical retinoids
Correct Answer ( D ) Explanation: Topical retinoids are pregnancy class C and should generally be avoided in pregnancy. Acne vulgaris is a very common disorder of the pilosebaceous follicles. Age of onset is usually between 10-17 years in females and 14-19 years in males. Acne tends to be more severe in males. Family history of acne is a strong risk factor for the development of acne. Other risk factors include certain medications (e,g, phenytoin, lithium, glucocorticoids, androgens), emotional stress, and occlusion and pressure on the skin. No conclusive evidence has correlated diet with increased risk or worsening of acne. Acne is caused by keratin plugs, which allows androgens and Propionibacterium acnes to interact. Acne lesions are usually located in areas with the largest, hormonally-responsive glands such as the face, neck, chest, upper back, and upper arms. Comedones are the main lesion associated with acne. Comedones can be open (blackheads) or closed (whiteheads). Other lesions include papules, pustules, and nodules. Severe acne is characterized by sinus tracts, caused by merged nodules. The severity of acne is based on lesion type, scarring, presence of sinus tracts, therapeutic response, and psychological impact of acne. The diagnosis of acne is based on physical examination. However, if there is high clinical suspicion for an underlying disorder, such as polycystic ovarian syndrome, certain laboratory tests may be required. Topical retinoids, topical antibiotics, or benzoyl peroxide are usually first-line medications for management of mild to moderate inflammatory acne. Oral antibiotics in combination with a topical retinoid and benzoyl peroxide are recommended for moderate to severe acne. Severe, recalcitrant, nodular acne is an indication for oral isotretinoin. Oral isotretinoin is pregnancy class X.
A 28-year-old woman with a history of pernicious anemia presents with significant depigmentation of the skin on her cheeks, hands and forearms. She has no history of damaging events to the skin or prior dermatologic disorders. Which of the following interventions would be the best initial step in managing this patient? Local liquid nitrogen application Narrowband UVB therapy Oral PUVA therapy Topical tacrolimus
Correct Answer ( D ) Explanation: Topical tacrolimus 0.1%, applied twice daily, is the first-line therapy for patients with vitiligo affecting less than 20% of the patient's body. Vitiligo is suspected in patients with any hypopigmentation in the color of their skin compared to the surrounding skin areas. The underlying cause of vitiligo is the destruction of melanocytes, or pigment cells. Often, there is an autoimmune component to this destruction and it may be seen in conjunction with diseases such as pernicious anemia, autoimmune thyroid disease, Addison disease, and type 1 diabetes. In the absence of an underlying autoimmune condition, other causes of hypopigmentation may be responsible. A history of using intralesional corticosteroids or liquid nitrogen over the affected skin may cause temporary loss of pigmentation, particularly in patients with a naturally olive or dark complexion. True vitiligo should also be distinguished from post-inflammatory hypopigmentation, as is seen in patients with a history of inflammatory skin conditions. A Wood's lamp can be used to accentuate vitiligo, as the hypopigmentation following an inflammatory condition will not enhance readily. Treating vitiligo is often a long process of trial-and-error. In patients with less than 20% involvement, topical tacrolimus can be recommended. Super-potent topical steroid creams may be used as well, but with the additional risk of skin atrophy in prolonged courses. Patients with 20-25% involvement may benefit more from narrowband UVB or oral PUVA therapy. However, patients should be counseled that there is a risk of severe phototoxic reactions with PUVA therapy. Generally, the fingertips and genitals are most difficult to treat, while the face and chest can be expected to respond well. Years of treatment are usually needed. Importantly, vitiligo increases a patient's risk of developing skin cancers, and more thorough skin screening methods should be considered.
A 25-year-old pregnant woman is being evaluated for vaginal irritation. Physical exam reveals small, flesh-colored, papillary growths on her vulva as shown. Examination of the cervix is unremarkable. Which of the following is the best initial treatment? Imiquimod cream Podophyllin solution Podophyllotoxin Trichloroacetic acid
Correct Answer ( D ) Explanation: Trichloroacetic acid is the first-line therapy for genital warts during pregnancy. It can be used for both external and internal warts. Condyloma acuminata, or genital warts, are caused by an infection with the human papillomavirus (HPV) types 6 and 11. It is a sexually transmitted infection that can be prevented with vaccination. Symptoms include flesh colored to white, exophytic or papillomatous growths in the genital area. In women, this can affect the vagina, cervix, vulva, oropharynx, perineum, and perianal areas. HPV can be spread via sexual contact or from mother to newborn during passage through the birth canal. Treatment in pregnancy should be initiated at 32 weeks gestation to allow healing before delivery. Treatment includes trichloroacetic acid solution, podophyllin, cryosurgery, surgical excision, or imiquimod cream application. Imiquimod cream (A), podophyllin solution (B), and podophyllotoxin (C) are all unsafe during pregnancy. Podophyllin is teratogenic.
During a routine physical exam on a 66-year-old man, he asks why his toenails have progressively become discolored. You note that multiple nails on his feet are thickened and are yellow-brown in color. Which of the follow is the most likely etiology of this man's condition? Candida albicans Malassezia furfur Staphylococcus aureus Trichophyton rubrum
Correct Answer ( D ) Explanation: Trichophyton rubrum is the most common cause of distal lateral subungual onychomycosis. Distal lateral subungual onychomycosis is the most common subtype of onychomycosis. Onychomycosis is an infection of the nail that can be caused by fungi, yeasts, and non-dermatophytes. Onychomycosis is the most common cause of abnormal nails. Risk factors for onychomycosis include advanced age, male sex, swimming, tinea pedis, psoriasis, immunodeficiency, and contact with people who have onychomycosis. While T. rubrum is the most common etiology of distal lateral subungual onychomycosis, other subtypes have different etiologies. Trichophyton mentagrophytes is the most common cause of white superficial onychomycosis. Patients with onychomycosis often present with discolored nail as the sole complaint, although severe infections can be associated with pain or burning. Distal lateral subungual onychomycosis typically presents with yellow or brown discoloration and thickening of the nail. White superficial onychomycosis presents with dull white spots on the surface of the nail. Tinea pedis frequently accompanies onychomycosis. KOH preparation is a quick in-office test that has high specificity for onychomycosis. Other laboratory studies that can be used to diagnose onychomycosis include culture, polymerase chain reaction, and calcofluor white staining. Treatment is not required unless the patient has underlying immunodeficiency, is at risk for cellulitis, or desires treatment for cosmetic reasons. Topical antifungal medications are typically used for mild disease or in patients who cannot tolerate systemic antifungal drugs. Systemic antifungal drugs result in faster infection clearing. Candida albicans (A) is the most common cause of fingernail onychomycosis. Yeast more frequently affects fingernails than toenails. Candida albicans is a common commensal organism normally found in the human oropharyngeal cavity, gastrointestinal tract, and vagina.
A 64-year old man presents with right-sided abdominal pain and the following rash. Which of the following is the most likely diagnosis? Coxsackie A16 Herpes simplex type 1 Rubeola Varicella zoster
Correct Answer ( D ) Explanation: Varicella Zoster is the cause of both varicella (chickenpox) and zoster (shingles). Chickenpox is generally an infection of childhood that is characterized by a vesicular rash in crops of varying stages. The transmission is via respiratory droplets and contact with ruptured vesicles. Shingles is a reactivation of the latent virus from the dorsal root ganglia. Shingles can occur at all ages but is most commonly seen in patients older than 50 years. Shingles presents in a unilateral dermatomal distribution of vesicles. It is associated with pain and burning that may precede the eruption by up to 72 hours. The rash evolves quickly from an erythematous, maculopapular eruption to a cluster of vesicles. The duration of illness is usually 7-10 days. Transmission is by contact with the ruptured vesicles and via respiratory droplets. Treatment consists of oral anti-viral medications (acyclovir or valacyclovir), aluminum acetate soaks and pain control. Vaccines are available for both chickenpox and shingles. The shingles vaccine is indicated in patients older than 60 years, and in some patients older than 50 years.
Which of the following is the first line treatment for scabies? Clotrimazole cream Lindane cream Mebendazole Permethrin cream
orrect Answer ( D ) Explanation: Permethrin cream is the treatment of choice for scabies and is applied from the neck down (include the head when involved) and rinsed off 8 to 14 hours later. Usually this is performed overnight. Scabies is caused by an obligate human parasite. Patients present with a pruritic rash that is often worse in the night. Skin findings include papules, nodules, burrows, and vesicular pustules. The distribution includes the interdigital spaces, wrists, ankles, waist, groin, and axillae. Pruritic nodules around the axillae, umbilicus, or on the penis and scrotum are highly suggestive of scabies. In children the head can also be involved. Look for burrows because these are pathognomonic of scabies and will be the best site to find mites. Scabies is a clinical diagnosis based on the typical rash and history.
