Dermatology MKSAP
Pitted keratolysis. a bacterial infection most commonly caused by Kytococcus sedentarius. The key features are waxy or scaly plaques, thickening of the plantar skin (keratoderma), small punctate erosions in the plaques that may coalesce to form broader erosions, and odor. Risk factors for infection include excess sweating (hyperhidrosis) and prolonged occlusion of the feet in footwear. Usually symptoms are minimal, with most complaints directed toward odor, but minor itching can occur. Treatment is best accomplished with topical antibiotics and keeping the feet dry, including the use of topical antiperspirants.
A 19-year-old man is evaluated for 4 to 5 months of persistent itching, thickening of the skin, and odor of the feet. He also has hyperhidrosis of the palms and soles. Medical history is otherwise unremarkable, and he takes no medications. On physical examination, vital signs are normal. Skin findings are shown. There is substantial odor of the feet. There are no changes to the toenails. The axillae and groin are unremarkable. Potassium hydroxide preparation of skin scrapings does not reveal fungal elements. Which of the following is the most likely diagnosis?
Begin an oral antihistamine and topical glucocorticoid. This patient has postscabetic pruritus, which follows an infestation caused by the ectoparasite Sarcoptes scabiei resulting in intense pruritus. Treatment of the patient and close contacts is required to eliminate the original infestation. Topical application of permethrin 5% cream is a first-line therapy. The cream is applied overnight to the entire body surface from neck to toes, including genitals and under fingernails. The lotion is removed by showering or bathing 8 to 14 hours following application. Repeat treatment in 7 to 10 days is usually recommended. Clothing, linens, and anything that has had contact with skin within the preceding 1 to 2 weeks must be thoroughly washed. Itching can persist for several weeks following treatment, and this alone does not constitute a treatment failure; however, treatment failure or reinfestation should be considered if new lesions continue to develop. The persistence of pruritus in the absence of reinfection or treatment failure, termed "postscabetic pruritus" can be treated with antihistamines, topical glucocorticoids, and, if severe, oral glucocorticoids can be used.
A 21-year-old man is evaluated 3 weeks following treatment of scabies. The patient lives alone, but his sexual partner had similar symptoms. Scabies was confirmed in both persons by microscopic examination of skin scrapings. Both were treated with two applications of 5% permethrin 2 weeks apart. Both patient and partner were adherent to the treatment protocol. The patient notes persistence of itching without the appearance of new lesions, whereas his partner is now asymptomatic. Which of the following is the most appropriate next step?
Chest radiography. This patient needs a chest radiograph to complete the evaluation of her erythema nodosum (EN). EN is the most common form of panniculitis, or inflammation of the fat, with most inflammation concentrated on the intralobular septae. Because the inflammation is deep under the skin, the clinical manifestation seen on the surface is often tender, ill-defined erythema with some substance on palpation, which may fade from an active inflammatory red-pink to dull brown. Most commonly, EN occurs bilaterally and symmetrically on the anterior shins; however, it may also appear in any fatty area. Although lesions will often come and go, most resolve over 4 to 6 weeks. EN is a nonspecific reaction pattern occurring in response to some systemic process. EN can be idiopathic, but the most common associations are streptococcal infection, hormones (including oral contraceptives, hormone replacement therapy, or pregnancy), inflammatory bowel disease, sarcoidosis, lymphoma, and medication reactions. The diagnosis of EN can be clinically based on the acute onset of tender nodules on the bilateral shins typically in a young woman. Biopsy is not necessary in typical lesions.
A 23-year-old woman is evaluated for 2 weeks of painful lumps on her legs. The lumps persist for several days and make it difficult for her to go to work as a waitress. She is a college student in Ohio where she has lived her whole life. She has not traveled outside of the state for the last 2 years. She has no swollen or painful joints. She denies abdominal pain, diarrhea, weight loss, night sweats, and fever. She is sexually active with one partner for the past 2 years. She is taking oral contraceptive pills. On physical examination, vital signs are normal. There are tender faint pink-brown nodules on the shins bilaterally. The throat and tonsils appear normal. There is no joint swelling. Pregnancy test is negative. Complete blood count, erythrocyte sedimentation rate , and antistreptolysin O titers are pending. Barrier contraceptive methods are recommended in lieu of oral contraceptives. Which of the following tests should be done next?
Erythema multiforme major. features the development of characteristic tricolored targetoid plaques, as this patient demonstrates on the extremities and face. In EM major, these targetoid plaques are accompanied by mucous membrane involvement. The most common cause of EM is infection, and herpes simplex virus 1 and 2 are the most commonly recognized, followed by Mycoplasma pneumoniae. The treatment of EM major is supportive, and most cases resolve in a week. Suppressive therapy may be necessary for patients who have relapses of EM with herpes outbreaks.
A 23-year-old woman is evaluated in the emergency department. Four days ago she developed a cold sore on her lower lip. This was followed by the development of painful sores throughout her mouth. The next day she developed a rash on her hands, arms, legs, and face, and eventually on her palms and soles. She takes no medications. On physical examination, vital signs are normal. The patient has pain in her mouth, but is in no acute distress. Erosions are present in the oropharynx. There are five distinct monomorphic clustered 2- to 3-mm erosions on the left lower lip. Skin findings on the palm are shown. The arms and face have lesions similar to those on the palm. There is no sloughing of the skin when shearing force is applied. The lesions affect about 7% body surface area. There is no corneal injection or tearing and no genital erosion or ulceration.Which of the following is the most likely diagnosis?
Topical mupirocin. Impetigo is most commonly caused by Staphylococcus aureus or beta-hemolytic streptococci. It is very contagious and most commonly seen in children. Impetigo can be either nonbullous or bullous impetigo. Bullous impetigo is a toxin-mediated process usually caused by production of an exfoliative toxin by S. aureus, which induces erythema and loss of the superficial layer of the epidermis. Nonbullous impetigo is the more common type and often affects the face or extremities. It appears as erythematous papules or pustules that rupture and then progress to erosions with overlying honey-colored crust. The diagnosis of impetigo often can be made based on clinical presentation; however, culture of the honey-colored crust can confirm the pathologic organism and obtain sensitivity testing, which is important when treating extensive disease or staphylococcal scalded skin syndrome. This patient has only a few lesions, so the best treatment would be topical mupirocin. Mupirocin is a topical antibiotic that inhibits bacterial protein synthesis. It has good activity against both S. aureus and beta-hemolytic streptococci. There has been limited reported antibiotic resistance to mupirocin, and it is usually well tolerated. Washes with chlorhexidine and diluted bleach baths also can be used.
A 24-year-old woman is evaluated for a 4-day history of a worsening pruritic rash on the chin. She is a kindergarten teacher. Medical history is unremarkable, and she takes no medications. On physical examination, vital signs are normal. Skin findings are shown. Which of the following is the most appropriate treatment?
Chronic paronychia. Chronic paronychia typically is present for 6 weeks or more and affects multiple fingers. Typical manifestations of chronic paronychia include red, swollen, and tender nail folds that lack a cuticle. It can also cause ridging and dystrophy of the nail plate. Chronic irritation from water or chemical contact is the primary cause. Candida species are often isolated. The cause of chronic paronychia is multifactorial, and an important component appears to be an eczematous process, which explains why patients with chronic paronychia respond better to topical glucocorticoid than topical antifungal therapy. The primary management includes minimizing wet work.
A 25-year-old woman is evaluated for finger pain that began approximately 6 weeks ago. She works as a hairdresser. She is otherwise healthy and takes no medications. On physical examination, vital signs are normal. Skin findings reveal ragged cuticles on most of her digits. On the third digit of the left hand, the nail fold is tender. Skin and nail findings are shown. Which of the following is the most likely cause of this patient's tender finger lesion?
Molluscum contagiosum infection. Molluscum contagiosum is a common cutaneous viral infection caused by the poxvirus molluscum contagiosum. It occurs in three settings: children, adults as a sexually transmitted disease, and AIDS patients. The lesions are flesh-colored to yellow smooth papules with a shiny surface and an umbilicated center. They can be located anywhere on the skin, but in adults they typically involve the genital area; in AIDS patients, they often involve the face. Diagnosis can be made by the clinical appearance. In immunocompromised patients, cryptococcosis, histoplasmosis, or Penicillium marneffei infections may resemble molluscum lesions and should be differentiated by skin biopsy. Although lesions can self-resolve, this may take months to years. Therapy includes destructive techniques including cryotherapy, salicylic acid, cantharidin, or physical removal with curettage.
A 25-year-old woman is evaluated for pruritic lesions on the legs and in the groin area that first appeared several months ago. The patient is otherwise in good health and takes no medications. On physical examination, vital signs are normal. Skin findings are shown. Which of the following is the most likely diagnosis?
Incision and Drainage. This patient has an abscess with no systemic signs of infection, so the most appropriate treatment would be incision and drainage. Gram stain and culture of pus from carbuncles and abscesses are strongly recommended, but treatment without these studies is reasonable in typical cases. Treatment with antibiotics is not indicated unless there are systemic signs of infection including fever (38 °C [100.4 °F]), tachycardia (>90/min), tachypnea (>24/min), an abnormal leukocyte count (>12,000/μL or <400/μL), or immunocompromise. This patient does not present with any of these indications for antibiotic therapy. If antibiotic therapy is indicated, empiric treatment of purulent skin and soft tissue infection (furuncle, carbuncle, and abscess) should include an agent that is active against methicillin-resistant Staphylococcus aureus (MRSA), for example, trimethoprim-sulfamethoxazole or doxycycline.
A 28-year-old man is evaluated for a 4-day history of a tender nodule on the left dorsal hand. The patient thought the lesion started as a "spider bite," and it continued to increase in size and tenderness. He has no fever or chills. No other lesions are present. Medical history is unremarkable, and he takes no medications. On physical examination, vital signs are normal. Skin findings are shown. The remainder of the examination is normal. Laboratory values, including leukocyte count , are within normal range. Which of the following is the most appropriate treatment?
Melanotic macule. Melanotic macule or mucosal lentigo is a small, well-circumscribed, brown-to-black macule. The most common location is the lower mucosal lip, but they can occur on any mucosal surface. They are the mucosal counterpart of a lentigo on the skin. They are typically solitary, but multiple macules can occur. Numerous mucosal lentigines are associated with various syndromes such as Peutz-Jeghers and Laugier-Hunziker syndromes. Peutz-Jeghers syndrome is an autosomal dominant hamartomatous polyposis syndrome characterized by hamartomatous polyps in the gastrointestinal tract, mucocutaneous pigmentation, and an increased risk of cancer. Laugier-Hunziker syndrome is an acquired, benign disorder characterized by lentigines on the lips and buccal mucosa. It not associated with any systemic disorder.
A 30-year-old woman is evaluated for a dark spot on the lower lip for several months' duration. Medical history is unremarkable, and she takes no medications. On physical examination, vital signs are normal. There is 2 × 3-mm perfectly round, well-circumscribed brown-to-black macule on the lower mucosal lip. Oral mucosa is otherwise normal.Which of the following is the most likely diagnosis?
Morbilliform drug reaction. morbilliform, or exanthematous, drug eruption, which is the most common form of cutaneous adverse drug reaction. Morbilliform eruptions begin 4 to 14 days after the initiation of a new medication. Characteristic skin findings begin as coalescing fine monomorphic papules on the trunk and spread distally and symmetrically. Peripheral eosinophilia or leukocytosis may be seen, but other signs of systemic involvement are not present. The therapy is to stop the medication and treat symptomatically with antihistamines and medium-potency topical glucocorticoids for a brief time while the reaction resolves.
A 35-year-old man is evaluated after 3 weeks of worsening sinus pain and congestion. He was prescribed amoxicillin-clavulanate. Four days into his treatment, he developed a rash. On physical examination, vital signs are normal. Skin findings are shown. There is purulent postnasal drainage noted in the oropharynx. There are no oral, genital, or corneal erosions. There are no findings on the palms, soles, wrists, or ankles. The patient has no skin pain, mouth ulcers, or dysuria. His conjunctivae are injected, but there is no ocular pain. Laboratory studies show peripheral eosinophilia. Other laboratory values, including creatinine, blood urea nitrogen, and liver chemistry tests, are unremarkable. Which of the following is the most likely diagnosis?
Discontinue adalimumab. Approximately one third of SCLE cases are drug induced. Tumor necrosis factor inhibitors such as adalimumab are a leading cause of drug-induced SCLE. Unlike psoriasis, SCLE is photodistributed, tends to burn more than itch, and has a lighter pink-to-violet tone when compared with the red tones of psoriasis. Psoriasis improves with sun exposure, whereas SCLE worsens with sun exposure. This patient's rash at presentation is different from the distribution and appearance of her psoriasis, and it is worsened in the sun rather than improved. These features argue against psoriasis treatment failure and point toward drug-induced SCLE. Medications should be evaluated as a cause of all cases of SCLE, particularly those affecting young white men who have a very low risk of developing lupus spectrum disease. Other common causative medications are hydrochlorothiazide, ACE inhibitors, NSAIDs, proton pump inhibitors, and terbinafine. Drug withdrawal typically leads to improvement in drug-induced SCLE.
A 38-year-old woman is evaluated for a new rash on the chest, arms, and back. It appeared 3 weeks ago. It burns and itches and has not responded to over-the-counter hydrocortisone cream. The rash substantially worsened following a vacation at the beach. Medical history is significant for psoriasis vulgaris with involvement of the elbows and knees with psoriatic arthritis for 3 years' duration. Her only medication is adalimumab, which she started 2 months ago. It cleared her elbows and knees in about 3 weeks. On physical examination, vital signs are normal. Representative skin findings are shown. There is no facial rash, hair loss, rash in the ears, oral ulcerations, or swollen joints. Laboratory studies show antinuclear antibody titer less than 1:40. Which of the following is the most appropriate treatment for this patient?
Dapsone. This patient has dermatitis herpetiformis (DH), and the most appropriate treatment is a gluten-free diet and dapsone. DH is a subepidermal autoimmune bullous disorder that is extremely pruritic. There are small tense vesicles and papules, which are rarely intact, so the usual presentation is excoriations on the elbows, knees, and buttocks. The diagnosis can be confirmed with skin biopsy for routine and direct immunofluorescence testing. Deposition of granular IgA in the dermal papillary tips is pathognomonic of dermatitis herpetiformis. While dapsone is effective in inducing a clinical remission of DH, a gluten-free diet is the preferred long-term therapy. DH has a strong association with celiac disease. Dapsone will successfully treat the skin symptoms of dermatitis herpetiformis, but does not treat the associated gastrointestinal disease. A gluten-free diet treats both the cause and the symptoms of both diseases. In patients with celiac disease, failure to maintain a gluten-free diet increases the risk for small bowel lymphoma. Prior to initiating therapy with dapsone, patients should be checked for glucose-6-phosphate dehydrogenase deficiency because these patients have a high risk of hemolysis on dapsone therapy.
A 40-year-old man is evaluated during a follow-up visit for an extremely pruritic skin eruption for several months that was recently diagnosed as dermatitis herpetiformis. He denies gastrointestinal symptoms and is otherwise healthy and takes no medications. On physical examination, vital signs are normal. There are numerous excoriations on elbows, knees, and buttocks with rare intact vesicles. In addition to a gluten-free diet, which of the following is the most appropriate treatment for this patient?
Excision. This patient has an epidermal inclusion cyst (sometimes called epidermoid cyst), and the most appropriate treatment is excision. The diagnosis of epidermal inclusion cysts is clinical. Epidermal inclusion cysts range from a few millimeters to several centimeters in size and are subepidermal, freely movable nodules with an epithelial lining and a core of accumulated keratin debris. They are most commonly found on the trunk. Epidermal inclusion cysts are often incorrectly referred to as "sebaceous cysts," a term that is erroneous because they possess keratin rather than sebum. Often they have a central punctum by which foul-smelling material can be expressed; the odor is derived from the presence of anaerobic bacteria. Epidermal inclusion cysts are benign but are frequently removed if they become bothersome to the patient. In this case, treatment is by excision with removal of the entire cyst wall.
A 40-year-old man is evaluated for a firm, flesh-colored lesion that has been growing on the back for several months. Foul-smelling material can be expressed from the lesion. The patient is bothered by the periodic drainage. He is otherwise healthy and takes no medications. On physical examination, vital signs are normal. There is a 3-cm subepidermal nodule with a central punctum on the upper back. There is no erythema or warmth of surrounding skin. Which of the following is the most appropriate treatment for this patient?
Basal cell carcinoma. the most common type of skin cancer. The lesion demonstrates typical findings with a translucent (pearly) papule and arborizing telangiectasias. It typically appears on sun-exposed areas in fair-skinned persons with a history of extensive sun exposure. It is usually asymptomatic and enlarges slowly over time. Although it rarely metastasizes, basal cell carcinoma can cause significant local tissue destruction if not removed.
A 44-year-old man is evaluated for a new lesion on the side of his face. It has been present for several months and is asymptomatic. When he shaves he cuts it, and it starts bleeding. He is otherwise healthy and takes no medications. On physical examination, vital signs are normal. Skin findings are shown. The remainder of the examination is normal. Which of the following is the mostly likely diagnosis?
Polyarteritis nodosa. cutaneous-only variant of polyarteritis nodosa (PAN). PAN is a medium-vessel vasculitis not associated with the development of ANCAs. The skin may be the only organ involved (cutaneous-only PAN) or it may be involved as part of a systemic disease. Biopsy of an affected organ will show medium-vessel vasculitis.
A 44-year-old woman is evaluated for painful nodules, ulcers, and skin changes on the lower legs of 2 years' duration. She takes no medications. On physical examination, vital signs are normal. Tender subcutaneous nodules, stellate ulcerations, and livido reticularis are evenly distributed bilaterally over her lower legs. The dorsalis pedis and posterior tibial pulses are normal. There are no varicosities present on the legs. The remainder of the examination is normal. Laboratory studies show an erythrocyte sedimentation rate of 65 mm/h. Skin biopsy shows vasculitis of a mid-sized arteriole in the subcutis. ANCA screen is negative. Antinuclear antibodies titer is 1:40. C3 and C4 values are normal. Rheumatoid factor and hepatitis B and C tests are negative. Stool is negative for occult blood, and urinalysis is unremarkable. Which of the following is the most likely diagnosis?
Inverse psoriasis. Based on the finding of the well-demarcated, erythematous plaques in intertriginous areas, this patient has inverse psoriasis. Psoriasis is a chronic inflammatory dermatosis that manifests with scaling, variably pruritic plaques that may be recalcitrant to topical therapy. There are many different patterns of psoriasis including classic psoriasis vulgaris (erythematous patches with a thick, adherent scale), inverse psoriasis (red, thin plaques with variable amount of scale in the axillae, under the breasts or pannus, intergluteal cleft, and perineum), sebopsoriasis (red, thin plaques in the scalp, eyebrows, nasolabial folds, central chest, and pubic area), and guttate psoriasis (0.5- to 2-cm red plaques that erupt suddenly on the trunk often after a group A streptococcal infection). Psoriasis can also involve the nails presenting as pit-like indentations and "oil spots" often involving multiple nails. Inverse psoriasis can be difficult to diagnosis because it often lacks the classic silvery scale. It also resembles other common dermatologic conditions such as tinea, intertrigo, and allergic contact dermatitis.
A 45-year-old man is evaluated for a 6-month history of pruritic rash in the inguinal and gluteal folds. He has used topical ketoconazole for 3 weeks with no improvement. Medical history is significant for type 2 diabetes mellitus. Medications are metformin and ketoconazole cream. On physical examination, vital signs are normal. BMI is 32. Occipital scalp has erythematous plaque with scale. Skin findings are shown. Similar findings are noted in the gluteal cleft. Elbows and knees are clear. Nail pitting is not present. Which of the following is the most likely diagnosis?
Potassium hydroxide examination. This patient's skin lesions are erythematous annular patches with noticeable surface scale. When confronted with an annular scaly patch, the most common diagnosis is tinea from a dermatophyte infection. Direct microscopic examination of KOH-prepared specimens is the simplest, cheapest method used for the diagnosis of dermatophyte infections of the skin. After scraping the leading edge of scale with a number 15 blade or the edge of the glass slide, apply 2 to 3 drops of KOH on the debris and then apply a coverslip. Evaluate the specimen initially with 10 power magnification. Tinea is confirmed by the presence of septated branching hyphae.
A 45-year-old man is evaluated for itching with dry scaling skin of 1 month's duration. His medical history is noncontributory, and he takes no medications. On physical examination, vital signs are normal. Skin findings are shown.The remainder of the examination is unremarkable. Which of the following is the most appropriate diagnostic test to perform next?
Localized scleroderma (morphea). Localized scleroderma is one of the scleroderma spectrum disorders, a group of diseases sharing the feature of skin hardening. The scleroderma spectrum disorders include systemic sclerosis (SSc), localized scleroderma, and scleroderma-like conditions. SSc is further characterized as two distinct subsets based on skin involvement: limited SSc and diffuse SSC. In limited SSc, scleroderma is restricted to the fingers and hands and, to a lesser extent, the face and neck. Scleroderma involving the fingers and hands, chest, abdomen, forearms, upper arms, and shoulders indicates diffuse SSc. Morphea is a localized form of scleroderma limited to one or more indurated plaques confined to the torso and proximal extremities. Although histologic findings of morphea are identical to those seen in patients with SSc, visceral manifestations and Raynaud phenomenon are absent. This patient has a generalized variant of morphea called pansclerotic morphea, which often appears in areas of friction and pressure, such as the waistband area or inframammary regions. Diffuse and limited SSc involve the fingers first, and sclerosis proceeds proximally, sometimes very rapidly.
A 47-year-old woman is evaluated for her skin "turning to leather." She notes that she had originally developed an itchy pink rash on the skin over her forearms, elbows, and upper arms. Eventually the rash turned to thick hard skin. She has similar skin findings in the area of her waistband. She denies symptoms of Raynaud phenomenon. On physical examination, vital signs are normal. Skin findings are shown. There are no changes over the face or lips. Which of the following is the most likely diagnosis?
Imidazole cream. Dermatophytosis or tinea of non-hair-bearing skin with limited involvement can be treated with imidazole cream applied once to twice daily for 2 to 4 weeks. Application should extend a few centimeters beyond the advancing border. For tinea pedis, the web spaces between the toes should be treated. Other topical agents including miconazole, clotrimazole, ketoconazole, ciclopirox, or terbinafine can also be used. Over-the-counter preparations are cost-effective options with good efficacy. Most infections will resolve but may recur and require retreatment. In immunosuppressed patients, recognition and treatment of superficial skin fungal infections is essential, as fungal infections can lead to epidermal breakdown and create a portal of entry for invasive pathogens. Tinea pedis is also a potential cause of recurrent bacterial cellulitis.
A 50-year-old man is evaluated for a several month history of itchy, scaly feet. It has persisted despite the application of a moisturizing lotion. He has no significant medical history and takes no medications. On physical examination, vital signs are normal. There are erythematous scaly patches on the sides of the feet and maceration between toes. Toenails are normal. Microscopic examination using potassium hydroxide preparation shows branching hyphae in the keratin (scale). Which of the following is the most appropriate treatment?
Prednisone. This patient has pyoderma gangrenosum, and a glucocorticoid, such as prednisone, is the preferred initial treatment. Typically required in doses of 1 mg/kg, prednisone is often effective in controlling pyoderma. To protect from long-term side effects of prolonged glucocorticoid use, steroid-sparing agents, immunosuppressants, intralesional glucocorticoids, or high-potency topical glucocorticoids are frequently used. Pyoderma gangrenosum is commonly associated with inflammatory bowel disease, hematologic abnormalities, and malignancies. The disease predominately affects the lower legs, but can be seen at any location. The beginning sign is often a tender pustule or red papule or nodule. This will quickly erode into an ulcer. Classic cases will have a rolled purplish border and undermined edges. As the ulcer resolves, it tends to heal with atrophic scarring in a cross-like or cribriform pattern. The ulcer is extremely painful. The diagnosis is one of exclusion, and other causes of ulceration need to be ruled out. Skin biopsies are not diagnostic. Surface cultures will grow myriad bacteria, which are most likely colonizing the ulcer and not causative.
A 52-year-old man is evaluated for a rapidly enlarging, painful ulcer on the leg. It started as a small red "pimple" approximately 2 weeks ago and has been expanding over the past week. Medical history is significant for ulcerative colitis. His only medications are sulfasalazine and folic acid. On physical examination, vital signs are normal. Skin findings are shown. Tissue culture is negative. Which of the following is the most appropriate initial treatment?
Porphyria cutanea tarda. Skin findings seen early in the disease include fragile skin with vesicles and bulla associated with milia (tiny proteinaceous cysts) formation on sun-exposed skin, particularly on the dorsal hands. PCT is caused by an accumulation of photosensitive porphyrins within the bloodstream and tissue. These photosensitizers enter the skin and upon exposure to ultraviolet A light in the 400- to 410-nm range cause damage to the skin. Later in the course of the disease, patients may develop hypo- or hyperpigmentation and hypertrichosis of the face. In some patients, scarring may result in thickening and calcification of the skin. Persons diagnosed with PCT should be evaluated for underlying liver disease, especially hepatitis C and hemochromatosis. Therapy is usually focused on avoiding sun exposure and decreasing the iron overload with phlebotomy, as well as treating the underlying cause of liver disease. Susceptibility factors that can exacerbate PCT to be avoided include alcohol use, smoking, and estrogens. The diagnosis can be made by finding elevated levels of porphyrins in the urine. A 24-hour urine evaluation will show elevated levels of uroporphyrin and coproporphyrin.
A 52-year-old man is evaluated for fragile skin and blisters on the dorsal hands of 2 years' duration. Medical history is significant for a 30-pack-year history of smoking and moderate alcohol consumption. He is a roofer and has had significant sun exposure. He is otherwise in good health and takes no medications. On physical examination, vital signs are normal. He has hypertrichosis on the face. Skin findings are shown. The remainder of the physical examination is normal. Which of the following is the most likely diagnosis?
Lupus pernio. a variant of sarcoidosis that involves granulomatous inflammation of the skin around the nares. Histopathology of sarcoidosis shows granulomatous inflammation of the affected tissue with noncaseating granulomas and minimal lymphocytic infiltration.
A 54-year-old woman is evaluated for lumps that have appeared around the outside of her nostrils over the last 5 months. She has had arthralgias for the past 6 months. She takes no medications. On physical examination, vital signs are normal. Skin findings are shown. The remainder of the skin examination is normal. Skin biopsy shows granulomas without necrosis or lymphocytic infiltration in the dermis. Which of the following is the most likely diagnosis?
Amyloidosis. Amyloid light chain amyloidosis is the most common type of amyloidosis; it is a plasma cell dyscrasia-related disease characterized by end-organ damage secondary to tissue deposition of monoclonal free λ or κ light-chain fibrils. Clinical symptoms and manifestations vary and are dictated by the tissue tropism of the amyloidogenic light chain. If amyloid deposits are identified on tissue biopsy, other types of amyloidosis should be excluded by typing, which can be done by κ/λ light-chain immunohistochemistry. Major clinical manifestations include proteinuria with worsening kidney function, restrictive cardiomyopathy, and hepatomegaly. Neurologic findings include a symmetric, distal sensorimotor neuropathy, carpal tunnel syndrome, and autonomic neuropathy with orthostatic hypotension. Skin manifestations are present in 30% to 40% of patients and include generalized waxy appearance, ecchymoses with minor pressure ("pinch purpura"), ecchymoses around the eyes ("raccoon eyes"), yellow waxy papules and plaques especially in a periorbital location, dystrophic nails, and macroglossia. Bleeding caused by acquired factor X deficiency may also occur.
A 60-year-old woman is evaluated for easy bruising and bleeding after minor trauma, and a rash around her eyes. Medical history is unremarkable, and she takes no medications. On physical examination, vital signs are normal. The patient has several ecchymoses located primarily on her arms and legs. Lesions around her eyes are shown. Hepatomegaly is present. The remainder of the physical examination is unremarkable. Urinalysis demonstrates 4+ proteinuria but is otherwise unremarkable. Which of the following is the most likely diagnosis?
Methotrexate. This patient has moderate to severe psoriasis (30% or more body surface area involvement) and should be treated with systemic agents. Patients with psoriasis covering more than 10% body surface area or those with psoriatic arthritis, recalcitrant palmoplantar psoriasis, pustular psoriasis, or psoriasis in challenging anatomic areas (groin, scalp) may be considered for systemic therapy. These include tumor necrosis factor inhibitors, acitretin, methotrexate, IL-23 and IL-17 inhibitors, and phototherapy. Tumor necrosis factor inhibitors, such as etanercept, adalimumab, and infliximab, are excellent options for treating patients with both severe psoriasis and psoriatic arthritis. The newer IL-12/IL-23 and IL-17 inhibitors have shown excellent efficacy in psoriasis treatment. Therapy with any of the systemic agents should be guided by a clinician experienced in their use, including appropriate evaluation for contraindications and careful monitoring.
A 60-year-old woman is evaluated for follow-up treatment of long-standing psoriasis. Medical history is significant for hypertension and hypercholesterolemia. Family history includes multiple family members with psoriasis. She has no joint symptoms, and her medications are atenolol and simvastatin. On physical examination, vital signs are normal. There is no joint swelling. She has a total of 30% body surface area involvement with psoriasis without nail involvement. Which of the following is the most appropriate treatment?
Discontinue hydrochlorothiazide. Pruritus in the absence of skin findings should be evaluated for underlying systemic causes. These include kidney disease, hyperthyroidism, hepatobiliary diseases, HIV infection, lymphoproliferative disorders (lymphoma), and myeloproliferative disorders (polycythemia vera). Drug-induced pruritus should also be considered. This patient has a normal complete blood count, liver chemistry tests, thyroid-stimulating hormone levels, serum creatinine, and sedimentation rate, making many of the systemic diseases unlikely. However, this patient is taking hydrochlorothiazide for hypertension. Hydrochlorothiazide, calcium channel blockers, opiates, and NSAIDs are all medications that can cause generalized pruritus without skin findings. In patients taking multiple medications, it can be challenging to determine which drug(s) may be contributing to pruritus, as patients may develop medication-induced itch even after months or years on a drug. The most appropriate management in this patient would be to discontinue hydrochlorothiazide and monitor for 2 to 4 weeks to detect improvement of his pruritus.
A 62-year-old man is evaluated for a 4-month history of itching all over his body. He has no fatigue, weight loss, or night sweats. His appetite is good. Medical history is significant for hypertension treated with hydrochlorothiazide. He has no risk factors for HIV infection. On physical examination, vital signs are normal. There are a few scattered excoriations on the arms and lower legs. There are no other significant skin findings and no lymphadenopathy. Laboratory studies, including complete blood count with differential, erythrocyte sedimentation rate , liver chemistry tests, serum creatinine , and thyroid-stimulating hormone level, are within normal range. Which of the following is the most appropriate initial management?
Amyopathic dermatomyositis. an underrecognized presentation of dermatomyositis that does not include muscle disease. These patients experience characteristic cutaneous features of dermatomyositis, such as the heliotrope sign, shawl sign, and Gottron papules, but muscle enzymes and strength testing are normal. Skin findings in dermatomyositis are photosensitive and tend to flare after sun exposure. Amyopathic dermatomyositis carries similar risk for underlying malignancy and pulmonary fibrosis. There is no strong consensus on how to screen for malignancy.
A 62-year-old woman is evaluated for a "sun allergy," manifesting as a rash on her scalp, eyelids, upper back, and knuckles. This started 2 years ago, but is less pronounced over the winter months. Medical history is unremarkable. Her only medication is hydrocortisone cream. On physical examination, vital signs are normal. Pink-violet edematous macules are present on the eyelids. The scalp has pink-violet diffuse scaly macules with some thinning of the hair. There is a poikilodermatous pink scaly plaque on the upper back and posterior neck. The metacarpophalangeal and proximal interphalangeal joints have pink-violet flat-topped papules on their dorsal surface. There are dilated periungual capillary loops on each finger, and all 10 cuticles are dystrophic. There are no swollen joints, no abnormalities on strength testing, and no oral ulcerations. Laboratory studies show antinuclear antibody titer of 1:640. All other laboratory values, including creatine kinase , aldolase, aspartate aminotransferase , and gamma-glutamyl transferase, are normal. Which of the following is the most likely diagnosis?
Narrowband ultraviolet B (UVB) therapy. has become the standard form of phototherapy used in the initial treatment of psoriasis. The light source emits a narrow band of UVB radiation, in this case 311 nm of ultraviolet light. This wavelength was chosen for its efficacy and the fact that this wavelength of light is not absorbed by DNA. The theory is that if the light is not absorbed by DNA, less skin damage will occur, and there will be far fewer skin cancers as a side effect of the therapy. Broadband UVB was the mainstay of therapy until the advent of narrowband UVB. Broadband is still used in some centers today. Broadband UVB emits light in the 280 to 320 nm range; 260 nm is the wavelength of light with the maximum absorption by DNA. DNA absorption of UVB drops off dramatically after 290 nm. Broadband UVB contains wavelengths of light capable of causing DNA damage, leading to ultraviolet skin damage and ultimately skin cancer.
A 64-year-old man is evaluated for treatment of extensive psoriasis on 20% body surface area, covering the knees, elbows, scalp, and trunk. Medical history is otherwise unremarkable, and he takes no medications.On physical examination, vital signs are normal. He has no fingernail changes and no arthritis. Skin findings are shown. Which of the following forms of phototherapy is the most appropriate initial treatment?
Compression therapy. This patient has a venous stasis ulcer, and the most appropriate additional management is compression therapy. Venous stasis ulcers are the most common leg ulcers. Most patients have a history of stasis dermatitis and often have some level of scarring and dyspigmentation on the bilateral lower extremities. Venous stasis ulcers usually occur on the distal lower leg, particularly the medial aspect of the ankle, and may result from a minor trauma, a medical procedure, or an acute stasis dermatitis flare. The symptoms vary from negligible discomfort to significant pain. The ulcers tend to have an irregular border and surrounding hyperpigmentation, and the skin and subcutaneous tissues are thickened, resulting in lipodermatosclerosis (fibrosing panniculitis of the subcutaneous tissue). Patients often have varicose veins and peripheral edema. Treatment is directed toward three main areas: reducing the peripheral edema, creating a wound environment that is conducive to healing, and treating any secondary infection that may be present. Reduction of peripheral edema is achieved by the use of compression stockings, pneumatic compression boots, and compression dressings (Unna boots). Compression is the key to venous ulcer healing.
A 65-year-old man is evaluated for a 2-month history of an ulcer on the left lower leg that will not heal. While the ulcer has been painful, there has been no significant change in this symptom. The ulcer is minimally exudative and has not been associated with increased warmth, swelling, or expanding erythema. Medical history is significant for hypertension, hyperlipidemia, and type 2 diabetes mellitus. Medications are rosuvastatin, enalapril, hydrochlorothiazide, and metformin. On physical examination vital signs are normal. Skin findings are shown. Ankle-brachial index is 0.94 on both sides. Which of the following is the most appropriate management for the ulcer?
Miliaria. Miliaria or "heat rash" can appear as superficial clear vesicles or as multiple discrete red papules due to occlusion of eccrine sweat ducts. When the gland is clogged superficially, there are minute pustules that rupture easily and can be wiped off (miliaria crystallina). Miliaria rubra causes deeper red papules and some pustules when the clog is deeper and more inflammation is present. Miliaria is often seen in the setting of fever and occlusion. A typical clinical situation is a patient who is immobilized, either from pain or following surgery, and the sweat glands are occluded as a result. Therapy is guided toward cooling the affected area, allowing air circulation.
A 65-year-old man is evaluated in the ICU for a rash limited to his back that was first noticed this morning. He was admitted to the ICU for hospital-acquired pneumonia following hip replacement surgery 3 days ago. Because of deteriorating respiratory function, he was intubated and placed on mechanical ventilation. His current medications are fentanyl and piperacillin-tazobactam. On physical examination, temperature is 38.3 °C (100.9 °F), blood pressure is 110/60 mm Hg, pulse rate is 115/min, and respiration rate is 18/min (ventilator set rate is 14/min). Pulmonary examination reveals diffuse crackles. Skin findings are shown. Which of the following is the most likely diagnosis?
Rheumatoid vasculitis. Elderly smokers with long-standing rheumatoid arthritis and high rheumatoid factor titers are at risk for rheumatoid vasculitis. Rheumatoid vasculitis commonly affects small to medium-sized vessels of the skin, digits, peripheral nerves, eyes, and heart. Small-vessel vasculitis (leukocytoclastic vasculitis) appears as palpable purpura. In medium-vessel disease, nodules, ulcerations, livedo reticularis, and digital infarcts can occur. Periungual purpura (Bywaters lesions) is the result of nailfold thrombosis and appears as purpuric papules on the digital pulp of a few digits and in the nail fold area.
A 68-year-old man is evaluated for 3 weeks of painful "blood blisters" on his legs and feet. He has noticed burning and tingling of his right foot and three toes over the last 2 weeks. Medical history is significant for rheumatoid arthritis for 22 years. He is a 60-pack-year cigarette smoker. He occasionally uses cocaine. He denies fever, chills, and night sweats, anorexia, or weight loss. Medications are hydroxychloroquine and methotrexate. On physical examination, temperature is 36.6 °C (97.8 °F), blood pressure is 134/79 mm Hg, and pulse rate is 82/min. Changes typical of destructive rheumatoid arthritis are apparent in the hands, wrists, elbows, and feet. Palpable purpura is present over the legs and ankles. Periungual purpura is present on three fingers. There is reduced sensitivity to pinprick and fine touch over the lateral right foot and dorsal lateral three toes. There is no murmur on his cardiac examination. Laboratory studies show substantially elevated rheumatoid factor titer. Antinuclear antibody titer is less than 1:40. ANCA screen is negative. Complement levels are normal. Results of kidney and liver chemistry tests are normal. Which of the following is the most likely cause of the patient's skin findings?
Interdigital intertrigo. The diagnosis of cellulitis often is made based on the clinical presentation of a well-demarcated warm and tender erythematous plaque. Bacteria enter through superficial breaks in the skin or gain access by hematogenous spread. Treatment of the maceration and fissuring in the toe web spaces can decrease the risk of recurrent cellulitis. This fissuring, maceration, and scaling are often due to tinea pedis, which allows entry for Streptococcus and Staphylococcus aureus to infect the lower extremity. In addition, attempts should be made to identify and treat other predisposing conditions for cellulitis, such as edema, obesity, eczema, and venous insufficiency.
A 71-year-old man is evaluated for erythema and tenderness of the left lower leg for 1 week's duration. This is the second similar episode of the left lower leg. The last episode was 2 months ago. He was previously treated successfully with antibiotics. On physical examination, temperature is 38.1 °C (100.6 °F), blood pressure is 125/75 mm Hg, respiration rate is 16/min, and pulse rate is 85/min. There is a well-demarcated, warm and tender erythematous patch on the anterior lower left leg extending from dorsal foot to mid shin. There is tissue maceration and fissuring between second and third toe spaces bilaterally. The remainder of the physical examination is normal. In addition to initiating antibiotic therapy, which of the following is the most appropriate management?
Halo nevus. are benign melanocytic nevi that are in the process of being attacked and eliminated by the immune system. They are characterized by a pigmented macule or papule with a surrounding "halo" of hypopigmented or depigmented skin. The halo gradually enlarges, and the mole shrinks until all that is left is a depigmented area on the skin that resembles a small area of vitiligo. These lesions are particularly common on the back in children, teenagers, and young adults.
An 18-year-old woman is evaluated for a mole on her back that has been changing in color for several weeks. There are no other associated symptoms. She has no significant medical history and takes no medications. On physical examination, vital signs are normal. Skin findings are shown. The remainder of the examination is unremarkable. Which of the following is the most likely diagnosis?
Biopsy. Actinic keratoses are red scaly papules and plaques that occur in sun-exposed areas, most often in those over age 50. They have a "gritty" texture, and early lesions are often easier to palpate than to see. Diagnosis is usually made clinically rather than with biopsy. Individual lesions are often treated with cryotherapy. In patients with a large number of actinic keratoses, areas with multiple lesions are best treated with topical preparations (such as 5-fluorouracil or imiquimod); photodynamic therapy may also be performed.
An 82-year-old woman is evaluated for a spot on her left cheek. Six months ago, she was diagnosed with an actinic keratosis. This lesion was treated with cryotherapy two times; however, the lesion is still persistent. On palpation, it is indurated. The lesion is shown.Which of the following is the most appropriate next step in management?
