SPEX Dermatology 4

Question 1

A patient presents with a well-demarcated, erythematous plaque with silvery scale on the elbow. The Auspitz sign is positive. What is the most likely diagnosis?

Accepted Answer

Psoriasis vulgaris

Answer

Psoriasis vulgaris classically presents with well-demarcated erythematous plaques with silvery scale and a positive Auspitz sign (pinpoint bleeding upon scale removal).

Question 2

Which dermatophyte is most commonly responsible for tinea capitis in the United States?

Accepted Answer

Trichophyton tonsurans

Answer

Trichophyton tonsurans is the most common cause of tinea capitis in the United States, typically not fluorescing under Wood's lamp.

Question 3

A 65-year-old man has a pearly, telangiectatic papule on his nose that has slowly enlarged over 2 years. Biopsy shows palisading nuclei at the periphery of tumor islands. What is the diagnosis?

Accepted Answer

Basal cell carcinoma

Answer

Basal cell carcinoma characteristically shows palisading of nuclei at the periphery of tumor nests on histology, with a pearly, telangiectatic clinical appearance.

Question 4

Which immunofluorescence pattern is characteristic of pemphigus vulgaris?

Accepted Answer

Intercellular IgG in a 'fishnet' pattern

Answer

Pemphigus vulgaris shows intercellular IgG deposition in a 'fishnet' or 'chicken wire' pattern on direct immunofluorescence due to anti-desmoglein antibodies.

Question 5

A patient with HIV presents with violaceous papules on the hard palate and lower extremities. What is the causative organism?

Accepted Answer

Human herpesvirus 8

Answer

Kaposi sarcoma, which presents with violaceous plaques and papules in immunocompromised patients, is caused by Human herpesvirus 8 (HHV-8).

SPEX Exam Practice Test

SPEX Exam Practice Test

SPEX Dermatology 4