Family Practice Exam Dermatology 3 — Questions and Answers
Question 1: A 22-year-old presents with intensely pruritic linear burrows between the fingers and on the wrists, worse at night. Close contacts are also affected. What is the treatment of choice?
- Permethrin 5% cream applied to entire body (Correct answer)
- Hydrocortisone cream
- Oral fluconazole
- Mupirocin ointment
Correct answer: Permethrin 5% cream applied to entire body
Permethrin 5% cream applied to the whole body from neck down and left overnight is the first-line treatment for scabies.
Question 2: A 55-year-old woman on hydrochlorothiazide develops erythema, bullae, and erosions in sun-exposed areas with facial involvement resembling a butterfly rash. Photosensitivity worsens. What is the most likely diagnosis?
- Drug-induced photosensitivity (Correct answer)
- Systemic lupus erythematosus
- Porphyria cutanea tarda
- Bullous pemphigoid
Correct answer: Drug-induced photosensitivity
Thiazide diuretics are a common cause of drug-induced photosensitivity reactions, which resolve upon discontinuation of the offending drug.
Question 3: A 40-year-old presents with tense bullae on the trunk and extremities with negative Nikolsky sign. Direct immunofluorescence shows linear IgG and C3 at the dermoepidermal junction. What is the diagnosis?
- Bullous pemphigoid (Correct answer)
- Pemphigus vulgaris
- Dermatitis herpetiformis
- Epidermolysis bullosa
Correct answer: Bullous pemphigoid
Bullous pemphigoid shows tense bullae with a negative Nikolsky sign and linear IgG/C3 at the basement membrane zone on direct immunofluorescence.
Question 4: A 30-year-old with celiac disease presents with intensely pruritic grouped vesicles on the elbows, knees, and buttocks. DIF shows granular IgA deposits in dermal papillae. What is the diagnosis?
- Dermatitis herpetiformis (Correct answer)
- Bullous pemphigoid
- Linear IgA bullous dermatosis
- Herpes zoster
Correct answer: Dermatitis herpetiformis
Dermatitis herpetiformis is strongly associated with celiac disease and shows granular IgA in dermal papillae on direct immunofluorescence.
Question 5: A 70-year-old develops unilateral vesicular eruption in a dermatomal distribution on the trunk with pain preceding the rash by 3 days. What complication is most important to prevent?
- Postherpetic neuralgia (Correct answer)
- Bacterial superinfection
- Scarring
- Visceral dissemination
Correct answer: Postherpetic neuralgia
Postherpetic neuralgia is the most common and debilitating complication of herpes zoster, especially in elderly patients, and antivirals given early help reduce its incidence.
Question 6: A 25-year-old man has annular, scaly, pruritic plaques on the trunk with central clearing. KOH preparation shows hyphae. What is the first-line treatment?
- Topical clotrimazole for 2-4 weeks (Correct answer)
- Oral griseofulvin for 6 weeks
- Topical mupirocin
- Systemic prednisone
Correct answer: Topical clotrimazole for 2-4 weeks
Tinea corporis is treated with topical antifungals such as clotrimazole for 2-4 weeks for localized disease.
Question 7: A 16-year-old presents with open and closed comedones, inflammatory papules, and a few nodules on the face. What is the most appropriate initial treatment for this moderate-severe acne?
- Topical retinoid plus oral antibiotic (Correct answer)
- Isotretinoin alone
- Topical benzoyl peroxide alone
- Oral corticosteroids
Correct answer: Topical retinoid plus oral antibiotic
Moderate-severe acne is treated with a combination of a topical retinoid (to normalize follicular keratinization) and an oral antibiotic (to reduce P. acnes).
Family Practice Exam Dermatology 3
A 22-year-old presents with intensely pruritic linear burrows between the fingers and on the wrists, worse at night.
Close contacts are also affected.
What is the treatment of choice?