General MCQ Flashcards

Which sign describes a subungual longitudinal pigmented band that extends onto the proximal nail fold, raising concern for melanoma?

Answer: Hutchinson sign

Hutchinson sign is periungual pigment extension and is an ominous indicator of subungual melanoma.

Stroking a lesion causing it to urticate (Darier sign) is characteristic of which condition?

Answer: Urticaria pigmentosa (mastocytosis)

Darier sign, wheal formation on rubbing, is seen in mastocytosis due to mast cell degranulation.

Which virus is the causative agent of molluscum contagiosum?

Answer: Poxvirus

Molluscum contagiosum is caused by a poxvirus and presents as umbilicated, dome-shaped papules.

The Koebner phenomenon, where lesions appear at sites of trauma, is classically seen in which disease?

Answer: Psoriasis

Psoriasis characteristically demonstrates the Koebner phenomenon, with new plaques forming along lines of skin injury.

Which topical agent is the first-line treatment for actinic keratosis field therapy?

Answer: 5-fluorouracil

Topical 5-fluorouracil is a standard field therapy for actinic keratoses, which are premalignant lesions.

A young adult presents with a single large 'herald patch' followed by a christmas-tree distribution of scaly macules. What is the diagnosis?

Answer: Pityriasis rosea

A herald patch preceding a christmas-tree pattern of oval scaly lesions along skin cleavage lines is diagnostic of pityriasis rosea.

Which cell type in the epidermis functions primarily in antigen presentation as part of the immune system?

Answer: Langerhans cell

Langerhans cells are dendritic antigen-presenting cells located in the stratum spinosum of the epidermis.