Dermatologist Certificate General 2 — Questions and Answers
Question 1: Which layer of the epidermis is responsible for cell division and renewal?
- Stratum corneum
- Stratum granulosum
- Stratum basale (Correct answer)
- Stratum spinosum
Correct answer: Stratum basale
The stratum basale contains mitotically active keratinocytes that continuously divide to renew the epidermis.
Question 2: A patient presents with discrete, flat-topped, polygonal, violaceous papules on the wrists. What is the most likely diagnosis?
- Psoriasis
- Lichen planus (Correct answer)
- Pityriasis rosea
- Secondary syphilis
Correct answer: Lichen planus
Lichen planus classically presents with the '6 P's': pruritic, planar, polygonal, purple papules and plaques.
Question 3: Which immunoglobulin is primarily found at the dermal-epidermal junction in bullous pemphigoid?
- IgA
- IgM
- IgG (Correct answer)
- IgE
Correct answer: IgG
Bullous pemphigoid is characterized by IgG autoantibodies targeting BP180 and BP230 antigens at the dermal-epidermal junction.
Question 4: A child presents with a 'strawberry tongue,' desquamating rash, and perioral pallor. What organism is responsible?
- Staphylococcus aureus
- Group A Streptococcus (Correct answer)
- Haemophilus influenzae
- Neisseria meningitidis
Correct answer: Group A Streptococcus
Scarlet fever is caused by Group A Streptococcus producing erythrogenic toxins, leading to the classic rash and strawberry tongue.
Question 5: Which dermatoscopic structure is most associated with melanoma?
- Comma vessels
- Atypical pigment network (Correct answer)
- Milia-like cysts
- Arborizing vessels
Correct answer: Atypical pigment network
An atypical (irregular) pigment network with variable thickness and abrupt termination at the periphery is a key dermoscopic feature of melanoma.
Question 6: Tinea versicolor is caused by which organism?
- Candida albicans
- Trichophyton rubrum
- Malassezia furfur (Correct answer)
- Epidermophyton floccosum
Correct answer: Malassezia furfur
Tinea versicolor (pityriasis versicolor) is caused by the dimorphic yeast Malassezia furfur, part of normal skin flora.
Question 7: Which vitamin deficiency causes pellagra, characterized by dermatitis, diarrhea, and dementia?
- Vitamin B1 (thiamine)
- Vitamin B3 (niacin) (Correct answer)
- Vitamin B12 (cobalamin)
- Vitamin C (ascorbic acid)
Correct answer: Vitamin B3 (niacin)
Pellagra results from niacin (vitamin B3) deficiency and classically presents with the '3 Ds': dermatitis, diarrhea, and dementia.
Dermatologist Certificate General 2
Which layer of the epidermis is responsible for cell division and renewal?