Dermatology Flashcards

A patient presents with a well-demarcated, silvery-scaled plaque on the extensor surface of the elbow. What is the most likely diagnosis?

Answer: Psoriasis

Psoriasis classically presents as well-demarcated erythematous plaques with silvery scales on extensor surfaces such as the elbows and knees.

Which finding is most associated with a melanoma rather than a benign nevus?

Answer: Irregular border and multiple colors

The ABCDE criteria for melanoma include Asymmetry, Border irregularity, Color variation, Diameter >6mm, and Evolution—irregular borders and multiple colors are hallmarks.

A patient with a history of atopy presents with intensely pruritic, flexural rashes since childhood. What is the most likely diagnosis?

Answer: Atopic dermatitis (eczema)

Atopic dermatitis typically begins in childhood, is associated with the atopic triad (asthma, allergic rhinitis, eczema), and preferentially affects flexural areas.

What is the first-line treatment for mild-to-moderate acne vulgaris characterized by comedones and a few inflammatory papules?

Answer: Topical retinoids and/or benzoyl peroxide

Topical retinoids normalize follicular keratinization and benzoyl peroxide has antimicrobial properties; both are recommended as first-line agents for mild-to-moderate acne.

A patient presents with a target-like skin lesion with central blistering after starting a new antibiotic. What condition should be suspected?

Answer: Erythema multiforme

Erythema multiforme is characterized by target lesions (three concentric zones) and is commonly triggered by HSV infection or medications such as sulfonamides and penicillins.

A unilateral, painful, vesicular rash following a dermatomal distribution in an elderly patient is most consistent with:

Answer: Herpes zoster (shingles)

Herpes zoster results from reactivation of varicella-zoster virus in a dorsal root ganglion, presenting as a unilateral vesicular rash in a dermatomal pattern with pain.