Dermatologist Certificate Skin Disorders and Diagnosis 1 — Questions and Answers
Question 1: Which skin condition is characterized by silvery-white plaques with well-defined borders most commonly found on the elbows and knees?
- Psoriasis (Correct answer)
- Eczema
- Rosacea
- Vitiligo
Correct answer: Psoriasis
Psoriasis presents as thick, silvery-white scaly plaques with sharply demarcated borders, classically on extensor surfaces like elbows and knees.
Question 2: What is the hallmark clinical feature of atopic dermatitis (eczema) in adults?
- Lichenification and pruritus in flexural areas (Correct answer)
- Vesicular eruption on palms and soles
- Annular scaling patches on the trunk
- Depigmented macules on sun-exposed skin
Correct answer: Lichenification and pruritus in flexural areas
Adult atopic dermatitis typically presents with lichenification and intense itching in flexural areas such as the antecubital and popliteal fossae.
Question 3: Which type of melanoma is most commonly found on the palms, soles, and nail beds?
- Acral lentiginous melanoma (Correct answer)
- Superficial spreading melanoma
- Nodular melanoma
- Lentigo maligna melanoma
Correct answer: Acral lentiginous melanoma
Acral lentiginous melanoma is the most common melanoma subtype in darker-skinned individuals and arises on acral surfaces including palms, soles, and subungual regions.
Question 4: What is the primary pathological finding in bullous pemphigoid?
- IgG autoantibodies targeting BP180 and BP230 at the dermoepidermal junction (Correct answer)
- IgA deposits in dermal papillae
- IgG autoantibodies targeting desmoglein 1 and 3
- T-cell mediated destruction of basal keratinocytes
Correct answer: IgG autoantibodies targeting BP180 and BP230 at the dermoepidermal junction
Bullous pemphigoid is caused by IgG autoantibodies against BP180 (collagen XVII) and BP230, proteins of the hemidesmosome at the dermoepidermal junction.
Question 5: Tzanck smear showing multinucleated giant cells is characteristic of which condition?
- Herpes simplex or varicella-zoster infection (Correct answer)
- Impetigo
- Molluscum contagiosum
- Pemphigus vulgaris
Correct answer: Herpes simplex or varicella-zoster infection
A positive Tzanck smear showing multinucleated giant cells is diagnostic of herpetic infections, including both herpes simplex virus and varicella-zoster virus.
Question 6: Which dermatological condition is associated with Nikolsky sign — skin separation with lateral pressure?
- Pemphigus vulgaris (Correct answer)
- Bullous pemphigoid
- Dermatitis herpetiformis
- Linear IgA bullous dermatosis
Correct answer: Pemphigus vulgaris
A positive Nikolsky sign, where gentle lateral pressure causes skin to shear and blister, is classically associated with pemphigus vulgaris due to loss of intraepidermal cohesion.
Dermatologist Certificate Skin Disorders and Diagnosis 1
Which skin condition is characterized by silvery-white plaques with well-defined borders most commonly found on the elbows and knees?