Bacterial Skin Infections
Abscess
collection of pus within the dermis and deeper skin tissues Present as painful, tender, fluctuant and erythematous nodules
Folliculitis
superficial bacterial infection of the hair follicles small, raised, erythematous, occasionally pruritic pustules less than 5 mm in diameter
MC spots affected are the lower extremities and face
Areas commonly affected by erysipelas
Spreading erythematous, non-fluctuant tender plaque More commonly found on the lower leg Streaks of lymphangitis may spread from the area to lymph nodes
Cellulitis common features
Cellulitis
Results from an infection of the dermis that often begins with some entry portal such as a wound, maceration between toes or fungal infection (e.g., tinea pedis)
Superficial cellulitis with dermal lymphatic involvement —> skin is edematous and raised
Erysipelas
Answer: a Case Six, Question 1 Which of the following would the dermatologist recommend for initial management? a. An urgent surgical consult (necrotizing fasciitis is a surgical emergency) b. IVfluidsandnarrowantibioticcoverage(doneedIVfluidsbutalsoneed broad spectrum coverage initially) c. Schedule an MRI for tomorrow (If MRI done, should be stat; could show edema along fascial plane but sensitivity and specificity not well defined; never delay surgery for MRI if necrotizing fasciitis is clinically suspected) d. Schedule a skin biopsy in am (if biopsy done, should be an immediate deep biopsy; if diagnosis is suspected and general surgeon is present, deep tissue can be obtained during exploratory procedure; involved fascia would be edematous and dull gray with areas of necrosis; should order Gram stain and C&S e. All of the above (no, only a)
HPI: Mr. Gorton is a 68-year-old man who presented to outpatient surgery for hernia repair. He reported that he had not been feeling well yesterday but did not wish to cancel his surgery. On PE, he was febrile, tachycardic, and found to have an expanding tender red rash on his left thigh. He was admitted to medicine and the dermatology service was consulted for evaluation of the rash. ▪ PMH: hypertension, diabetes mellitus type 2 ▪ Medications: lisinopril, insulin, oxycodone ▪ Allergies: none ▪ Family history: noncontributory ▪ Social history: retired, lives with his wife ▪ Health-related behaviors: no alcohol, tobacco, or drug use ▪ ROS: fatigue, rash is very painful; deep bruise occurred last week while cutting wood in area of rash; also had skin tear from branch Vital signs: T 102.5, HR 110, BP 90/50, RR 20 ▪ General: ill-appearing gentleman lying in bed ▪ Skin: ill-defined, large erythematous plaque with central dusky blue patches, which are anesthetic; upon re- examination 60 minutes later the redness had spread; the subcutaneous tissue had a woody induration Which of the following would the dermatologist recommend for initial management? a. An urgent surgery consult b. IV fluids and narrow antibiotic coverage c. Schedule an MRI for tomorrow d. Schedule a skin biopsy in am e. All of the above
Answer: b What is the most likely diagnosis? a. Bacterial folliculitis (Would expect pustules and papules centered on hair follicles. Without systemic signs of infection) c. Necrotizing fasciitis (Would expect rapidly expanding rash, usually appears as a dusky, edematous, red plaque. In this setting, it is always appropriate to ask the question, "Could this be necrotizing fasciitis?") d. Stasis dermatitis (Although found in similar location, stasis dermatitis often presents on both legs with itch, some pain, and scale, which may erode or crust. There should not be fever or elevated WBC) e. Tinea corporis (Would expect annular plaque with elevated border and central clearing. Painless, but itchy without fever or elevated WBC)
HPI: Mr. Tolson is a 55-year-old man who presents with 5 days of worsening right lower extremity pain and a red rash. He reports recent fevers and chills since he returned from a camping trip last week. ▪ PMH: arthritis ▪ Medications: occasional NSAIDs, multivitamin ▪ Allergies: no known drug allergies ▪ Family history: father with history of melanoma ▪ Social history: lives in the city with his wife, two grown children ▪ Health-related behaviors: no alcohol, tobacco or drug use ▪ ROS: able to bear weight, no itching Vital signs: T 100.2, HR 80, BP 120/70, RR 18 ▪ Skin: erythematous plaque with ill- defined borders over the right medial malleolus that is tender to palpation. ▪ Tender, slightly enlarged right inguinal lymph node ▪ Laboratory data: WBC 12,000 (75% neutrophils, 10% bands) What is the most likely diagnosis? a. Bacterial folliculitis b. Cellulitis c. Necrotizingfasciitis d. Stasis dermatitis e. Tinea corporis
Answer: c What is the next best step in management? a. Apply topical antibiotics (not effective) b. Apply topical steroids, compression wraps, and encourage leg elevation (this is the treatment for stasis dermatitis, not cellulitis) c. Begin antibiotics immediately with coverage for Gram positive bacteria and encourage leg elevation d. Order an imaging study (radiographic examination is not necessary for routine evaluation of patients with cellulitis) e. Hospital admission for IV antibiotics (admission only with differential including deeper/necrotizing infection; severely immunocompromised or non-compliant patient; non-response to oral outpatient treatment; signs of systemic toxicity)
HPI: Mr. Tolson is a 55-year-old man who presents with 5 days of worsening right lower extremity pain and a red rash. He reports recent fevers and chills since he returned from a camping trip last week. ▪ PMH: arthritis ▪ Medications: occasional NSAIDs, multivitamin ▪ Allergies: no known drug allergies ▪ Family history: father with history of melanoma ▪ Social history: lives in the city with his wife, two grown children ▪ Health-related behaviors: no alcohol, tobacco or drug use ▪ ROS: able to bear weight, no itching Vital signs: T 100.2, HR 80, BP 120/70, RR 18 ▪ Skin: erythematous plaque with ill- defined borders over the right medial malleolus that is tender to palpation. ▪ Tender, slightly enlarged right inguinal lymph node ▪ Laboratory data: WBC 12,000 (75% neutrophils, 10% bands) Based on Mr. Tolson's history and findings, what is the next best step in management? a. Apply topical antibiotics b. Apply topical steroids, compression wraps, and encourage leg elevation c. Begin oral antibiotics immediately with coverage for Gram positive bacteria and encourage leg elevation d. Order an imaging study e. Hospital admission for IV antibiotics
5 day course of antibiotics is usually sufficient
How long should antibiotics be prescribed in most cases
Erysipelas
Large, shiny erythematous plaque with sharply demarcated borders located on the leg
Group A Strep
MCC of cellulitis
Staph aureus Could also be haemophilus
MCC of erysipelas
Answer: b What is the most likely diagnosis? a. Acne vulgaris (would expect comedones, papules, and pustules, but not crusted plaques) b. Impetigo c. Orolabial HSV (would expect grouped and confluent vesicles with an erythematous rim; can evolve to crusting and be confused with impetigo) d. Seborrheic dermatitis (would expect erythematous patches and plaques with a greasy, yellow scale) e. Tinea faciei (would expect erythematous, annular scaly plaques but often are erythematous with slight scale)
Mr. Holden is a 17-year-old man who presents to his primary care provider with a three-week history of a facial rash. The rash is not painful, but occasionally burns and itches. ▪ About a month ago he babysat his 2 year old niece and she had "a rash on the face." ▪ He tried over the counter hydrocortisone cream with no relief. What is the most likely diagnosis? a. Acne vulgaris b. Impetigo c. OrolabialHSV d. Seborrheic dermatitis e. Tinea faciei
Answer: e Which of the following treatment recommendations is most appropriate for Danny? a. Hand washing to reduce spread b. Topical or oral antibiotics c. Wash the affected area with antibacterial soap d. Check to see if his niece still has her rash e. All of the above
Mr. Holden is a 17-year-old man who presents to his primary care provider with a three-week history of a facial rash. The rash is not painful, but occasionally burns and itches. ▪ About a month ago he babysat his 2 year old niece and she had "a rash on the face." ▪ He tried over the counter hydrocortisone cream with no relief. Which of the following treatment recommendations is most appropriate for Danny? a. Hand washing to reduce spread b. Topicalororalantibiotics c. Wash the affected area with antibacterial soap d. Check to see if his niece still has her rash e. All of the above
Dicloxacillin • Cephalexin • Erythromycin (some strains of Staphyloccocus aureus and Streptococcal pyogenes may be resistant) • Clindamycin • Amoxicillin/clavulanate • If concern for MRSA, clindamycin, trimethoprim- sulfamethoxazole, or doxycycline can be used
Oral ABX that can be used for extensive impetigo, multiple people infected or to treat ecthyma
Local trauma Spread of previous infection (furuncle, ulcer, blood born infection-rare) Pre-existing skin infection due to tinea pedis/foot infections Inflammation Edema and impaired lymphatics
Risk factors for cellulitis
Treat for community-associated MRSA and strep → clindamycin, TMP/SMX, or doxycycline + amoxicillin; work with dermatology and infectious disease specialists
Purulent cellulitis treatment guidelines
Mupirocin, retapumulin
Topical ABX for impetigo
Cleanse with antibacterial soap Superficial pustules will rupture and drain spontaneously Oral or topical anti-staphylococcal agents as mupirocin or retapamulin ointment; topical clindamycin solution/lotion may be used Deep lesions of folliculitis represent small follicular abscesses and should be drained
Treatment for folliculitis
treat for β-hemolytic streptococci (group A streptococcus)→cephalexin, amoxicillin, amoxicillin-clavulanate, dicloxacillin, or clindamycin
Treatment for non-purulent cellulitis
Severe or extensive disease (e.g., involving multiple sites) • Rapid progression in presence of associated cellulitis • Signs and symptoms of systemic illness • Associated comorbidities or immunosuppression • Extremes of age • Abscess in an area difficult to drain (e.g., face, hand, or genitalia) • Associated septic phlebitis • Lack of response to I&D alone
When are ABX recommended for abscesses
Features of erysipelas
pain, bright erythema, and plaque-like edema with a sharply defined margin to normal tissue Plaques can develop into Bullae Has a high white count >20,000 Patients also have chills, fever, headache, N/V and joint pain
Answer: e What is the next best step in management? a. Incision and drainage (incision and drainage is the treatment of choice for abscesses) b. Topical antibiotics (not effective) c. Offer HIV test (patients with risk factors for HIV should be offered an HIV test, e.g. IVDU in this patient) d. a and b e. a and c
▪ HPI: Mr. Hammel is a 27-year-old man with a history of "skin popping" (subcutaneous or intradermal injection of drug) who presents to the emergency department with a painful, enlarging mass on his right arm for the last two days. ▪ PMH: History of skin and soft tissue infections, hospitalized with MRSA bacteremia two years ago ▪ Medications: none ▪ Allergies: no known drug allergies ▪ Family history: father with diabetes, mother with hypertension ▪ Social history: lives with friends in an apartment, works in retail ▪ Health-related behaviors: IVDU (intravenous drug use), including skin popping. No tobacco or alcohol use. ▪ ROS: no fevers, sweats or chills What is the next best step in management? a. Incision and drainage b. Topical antibiotics c. Offer HIV test d. a and b e. a and c
Answer: e Which of the following recommendations would you provide Mr. Anders? a. Prescribe oral antibiotics b. Stop shaving that area c. Wash the area daily (antibacterial soap may be used) d. Check with his girlfriend to see if she has any breakout e. All of the above
▪ Mr. Anders is a 19-year-old man who presents to dermatology clinic with two weeks of multiple "pimples" in his groin. He is concerned he has an STD. ▪ When asked, he reports occasionally shaving his pubic hair ▪ Sexual history reveals one female partner in the last year Which of the following recommendations would you provide Mr. Anders? a. Prescribe oral antibiotics b. Stop shaving that area c. Wash the area (antibacterial soap may be used) d. Check with his girlfriend to see if she has any breakout e. All of the above
