A physician-validated, board-style question from the Active Transport QBank. Try it, then check the reasoning for every option.
A 10-month-old girl is brought to the clinic by her mother with skin lesions on her chest. The mother says that she noticed the lesions 24 hours ago and that they have not improved. The patient has no significant past medical history. She was born at term by spontaneous transvaginal delivery with no complications, is in the 90th percentile on her growth curve, and has met all developmental milestones. Upon physical examination, several skin-colored umbilicated papules are visible. Which of the following is the most appropriate treatment of this patient's likely diagnosis?
-
A
AcyclovirIncorrect. Acyclovir treats HSV (vesicles on erythematous base, painful, not umbilicated) — not molluscum, which is a poxvirus.
-
B
Topical antifungal therapyIncorrect. Topical antifungals treat tinea or candida infections (scaly plaques or moist intertriginous lesions), not the umbilicated papules of molluscum.
-
C
Wide-spectrum antibioticsIncorrect. Antibiotics treat bacterial infections (impetigo, cellulitis) — not viral umbilicated papules.
-
D
Cryotherapy or podophyllotoxin (0.15% topically)Correct. Cryotherapy and podophyllotoxin are accepted treatments for molluscum contagiosum, although watchful waiting is also reasonable in immunocompetent children.
-
E
Oral isotretinoinIncorrect. Isotretinoin is reserved for severe nodulocystic acne and would be inappropriate (and teratogenic) for an infant — molluscum contagiosum is treated with watchful waiting, cryotherapy, or podophyllotoxin.
↑ Tap an answer to reveal the reasoning
Answer: D. An otherwise healthy infant with skin-colored umbilicated papules on the chest has molluscum contagiosum, a benign cutaneous infection caused by the molluscum contagiosum virus (a poxvirus, MCV-1 most commonly in children). Lesions are characteristically dome-shaped, flesh-colored or pearly papules with a central umbilication (dell), 2–5 mm in diameter, often distributed in clusters from autoinoculation. In children, they typically appear on the trunk, extremities, and face.
In IMMUNOCOMPETENT children, molluscum is self-limited and resolves spontaneously over months to a few years, so observation is reasonable. However, when treatment is desired (cosmetic concerns, spread, irritation), options include cryotherapy (liquid nitrogen — destruction by freezing), curettage, cantharidin, or topical podophyllotoxin (an antimitotic). All work by inducing local inflammation and immune response or direct destruction of the lesion. In sexually active adults, genital molluscum is treated for the same reasons.
Note: in immunocompromised patients (e.g., HIV/AIDS), molluscum can be widespread, large, and refractory — and warrants both treatment and evaluation for the underlying immunodeficiency.
**Why each option:**
**A.** Acyclovir treats HSV (vesicles on erythematous base, painful, not umbilicated) — not molluscum, which is a poxvirus.
**B.** Topical antifungals treat tinea or candida infections (scaly plaques or moist intertriginous lesions), not the umbilicated papules of molluscum.
**C.** Antibiotics treat bacterial infections (impetigo, cellulitis) — not viral umbilicated papules.
**D.** Correct. Cryotherapy and podophyllotoxin are accepted treatments for molluscum contagiosum, although watchful waiting is also reasonable in immunocompetent children.