CDT Common Skin Conditions & Treatment 3

Question 1

A patient presents with grouped vesicles on an erythematous base following a dermatomal distribution on the trunk. Which condition does this describe?

Accepted Answer

Herpes zoster (shingles)

Answer

Herpes zoster follows a dermatomal distribution due to reactivation of the varicella-zoster virus in a dorsal root ganglion.

Question 2

Which layer of the epidermis is primarily affected in the blister formation of pemphigus vulgaris?

Accepted Answer

Stratum spinosum (suprabasal)

Answer

In pemphigus vulgaris, autoantibodies against desmoglein-3 cause acantholysis (separation of keratinocytes) within the suprabasal stratum spinosum.

Question 3

A patient with acne vulgaris has predominantly open and closed comedones with few inflammatory lesions. This is classified as:

Accepted Answer

Mild comedonal acne

Answer

Predominantly comedonal lesions (blackheads and whiteheads) with minimal inflammation represent mild comedonal acne.

Question 4

Patch testing is the gold standard diagnostic tool for which condition?

Accepted Answer

Allergic contact dermatitis

Answer

Patch testing identifies type IV (delayed) hypersensitivity reactions and is the definitive test for allergic contact dermatitis.

Question 5

Which clinical feature best differentiates cellulitis from necrotizing fasciitis in the emergency setting?

Accepted Answer

Pain out of proportion to physical findings

Answer

Pain disproportionate to the visible skin findings is a red flag for necrotizing fasciitis, as the deep fascial destruction causes severe pain before overlying skin changes appear.

(CDT) Certified Dermatology Tech Practice Test

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CDT Common Skin Conditions & Treatment 3