Dermatologist Certificate Dermatologist Certificate MCQ 3 — Questions and Answers
Question 1: Which of the following is the first-line treatment for onychomycosis caused by dermatophytes?
- Topical clotrimazole
- Oral terbinafine (Correct answer)
- Oral fluconazole
- Topical ciclopirox
Correct answer: Oral terbinafine
Oral terbinafine is the first-line treatment for dermatophyte onychomycosis due to its high cure rates and fungicidal activity.
Question 2: A 60-year-old presents with a pearly, rolled border nodule on the nose with telangiectasias and central ulceration. What is the most likely diagnosis?
- Squamous cell carcinoma
- Basal cell carcinoma (Correct answer)
- Keratoacanthoma
- Merkel cell carcinoma
Correct answer: Basal cell carcinoma
A pearly nodule with rolled borders, telangiectasias, and central ulceration on sun-exposed skin of an older patient is classic for nodular basal cell carcinoma.
Question 3: Which autoantibody is most specifically associated with pemphigus vulgaris?
- Anti-BP180 (BPAG2)
- Anti-desmoglein 3 (Correct answer)
- Anti-desmoglein 1
- Anti-laminin-332
Correct answer: Anti-desmoglein 3
Pemphigus vulgaris is caused by IgG antibodies against desmoglein 3, leading to acantholysis and suprabasal blisters.
Question 4: Nikolsky's sign, where lateral pressure causes the skin to slide and blister, is positive in which condition?
- Bullous pemphigoid
- Pemphigus vulgaris (Correct answer)
- Dermatitis herpetiformis
- Epidermolysis bullosa acquisita
Correct answer: Pemphigus vulgaris
Nikolsky's sign is positive in pemphigus vulgaris due to the fragile suprabasal cleavage plane caused by desmoglein 3 autoantibodies.
Question 5: Which topical calcineurin inhibitor is approved for use in children as young as 2 years old for atopic dermatitis?
- Tacrolimus 0.1%
- Pimecrolimus 1%
- Tacrolimus 0.03% (Correct answer)
- Crisaborole 2%
Correct answer: Tacrolimus 0.03%
Tacrolimus 0.03% ointment is approved for children aged 2–15 years, while the 0.1% formulation is reserved for adults.
Question 6: A patient presents with pruritic, flesh-colored papules in a linear arrangement on the wrist and forearm after touching a plant. The pattern suggests which phenomenon?
- Koebner phenomenon (Correct answer)
- Phytophotodermatitis
- Blaschko's lines
- Dermatographism
Correct answer: Koebner phenomenon
The Koebner (isomorphic) phenomenon describes new lesions arising at sites of trauma or irritation, seen in conditions like lichen planus and psoriasis.
Question 7: Which mite is responsible for scabies infestation in humans?
- Demodex folliculorum
- Sarcoptes scabiei var. hominis (Correct answer)
- Cheyletiella yasguri
- Dermatophagoides pteronyssinus
Correct answer: Sarcoptes scabiei var. hominis
Scabies is caused by the burrowing mite Sarcoptes scabiei var. hominis, which is transmitted through close physical contact.
Dermatologist Certificate Dermatologist Certificate MCQ 3
Which of the following is the first-line treatment for onychomycosis caused by dermatophytes?