CDT Common Skin Conditions & Treatment 3 — Questions and Answers
Question 1: A patient presents with grouped vesicles on an erythematous base following a dermatomal distribution on the trunk. Which condition does this describe?
- Herpes simplex virus type 1
- Herpes zoster (shingles) (Correct answer)
- Contact dermatitis
- Bullous pemphigoid
Correct answer: Herpes zoster (shingles)
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?
- Stratum corneum
- Stratum granulosum
- Stratum spinosum (suprabasal) (Correct answer)
- Stratum basale
Correct answer: Stratum spinosum (suprabasal)
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:
- Severe nodulocystic acne
- Mild comedonal acne (Correct answer)
- Moderate papulopustular acne
- Acne fulminans
Correct answer: Mild comedonal acne
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?
- Irritant contact dermatitis
- Allergic contact dermatitis (Correct answer)
- Atopic dermatitis
- Seborrheic dermatitis
Correct answer: Allergic contact dermatitis
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?
- Presence of fever
- Pain out of proportion to physical findings (Correct answer)
- Skin erythema and warmth
- Leukocytosis on CBC
Correct answer: Pain out of proportion to physical findings
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.
Question 6: A 45-year-old patient has multiple skin-colored soft pedunculated growths in the axillae and neck folds. What are these lesions called?
- Dermatofibromas
- Acrochordonas (skin tags) (Correct answer)
- Neurofibromas
- Lipomas
Correct answer: Acrochordonas (skin tags)
Acrochordons (skin tags, or fibroepithelial polyps) are benign pedunculated growths commonly found in skin folds and areas of friction.
Question 7: Calcineurin inhibitors such as tacrolimus and pimecrolimus are used in atopic dermatitis primarily to:
- Kill Staphylococcus aureus colonization
- Avoid the side effects of long-term corticosteroid use (Correct answer)
- Moisturize the skin barrier
- Reduce IgE serum levels
Correct answer: Avoid the side effects of long-term corticosteroid use
Calcineurin inhibitors are non-steroidal anti-inflammatory agents that avoid skin atrophy and other side effects associated with prolonged topical corticosteroid use.
CDT Common Skin Conditions & Treatment 3
A patient presents with grouped vesicles on an erythematous base following a dermatomal distribution on the trunk.
Which condition does this describe?