Dermatologist Certificate Dermatologist Certificate MCQ 4 — Questions and Answers
Question 1: A patient with HIV presents with diffuse brownish-red macules and papules on the palms and soles. Which diagnosis should be considered first?
- Kaposi's sarcoma
- Secondary syphilis (Correct answer)
- Pityriasis rosea
- Drug eruption
Correct answer: Secondary syphilis
Palm and sole involvement is a hallmark of secondary syphilis, which must be ruled out in any sexually active or immunocompromised patient.
Question 2: Which finding on dermoscopy is most characteristic of a melanoma?
- Comma vessels
- Arborizing vessels
- Atypical pigment network with regression (Correct answer)
- Milia-like cysts
Correct answer: Atypical pigment network with regression
An atypical (irregular/broadened) pigment network with areas of regression is a major dermoscopic feature suggestive of melanoma.
Question 3: A 25-year-old woman develops a butterfly-shaped malar rash after sun exposure. ANA is positive. Which skin finding would further support systemic lupus erythematosus?
- Discoid plaques with follicular plugging
- Livedo reticularis
- Periungual telangiectasias
- Photosensitive malar rash sparing the nasolabial folds (Correct answer)
Correct answer: Photosensitive malar rash sparing the nasolabial folds
The malar rash of SLE classically spares the nasolabial folds, which distinguishes it from rosacea and seborrheic dermatitis.
Question 4: Which gene is most commonly mutated in familial melanoma?
- BRAF
- CDKN2A (Correct answer)
- KIT
- NRAS
Correct answer: CDKN2A
CDKN2A (encoding p16/INK4a) is the most frequently mutated gene in hereditary melanoma-prone families.
Question 5: A teenager presents with open and closed comedones without inflammatory lesions. Which topical agent is most appropriate as first-line monotherapy?
- Topical clindamycin
- Topical tretinoin (Correct answer)
- Benzoyl peroxide
- Topical dapsone
Correct answer: Topical tretinoin
Topical retinoids like tretinoin are first-line for comedonal acne because they normalize follicular keratinization.
Question 6: Which Wood's lamp finding is associated with erythrasma?
- Blue-white fluorescence
- Bright green fluorescence
- Coral-red fluorescence (Correct answer)
- No fluorescence
Correct answer: Coral-red fluorescence
Erythrasma caused by Corynebacterium minutissimum produces coral-red fluorescence under Wood's lamp due to porphyrin production.
Question 7: A 55-year-old construction worker has a 2 cm hyperkeratotic, ulcerated lesion on the lower lip with regional lymphadenopathy. What is the most likely diagnosis?
- Actinic cheilitis
- Squamous cell carcinoma (Correct answer)
- Keratoacanthoma
- Herpes labialis
Correct answer: Squamous cell carcinoma
Squamous cell carcinoma of the lip is common in sun-exposed, fair-skinned individuals and can metastasize to regional nodes.
Dermatologist Certificate Dermatologist Certificate MCQ 4
A patient with HIV presents with diffuse brownish-red macules and papules on the palms and soles.
Which diagnosis should be considered first?