Molluscum contagiosum
MC; molluscum; pox virus warts; water warts
Molluscum contagiosum is a common pox-virus skin infection presenting as discrete dome-shaped pearly papules with characteristic central umbilication. It predominantly affects children, immunosuppressed adults (HIV with CD4 < 200, transplant recipients, ICI patients) and athletes / wrestlers via skin-to-skin contact. Sexually transmitted in adult genital MC. In skin-oncology clinic it is a frequent diagnostic mimic of sebaceous hyperplasia, BCC, milia and trichoepithelioma. Most cases self-resolve over 6–18 months; treatment is offered for cosmetic concern, spread prevention or in immunocompromised patients where the disease can be extensive and persistent.
Clinical features
- Multiple discrete dome-shaped papules, 2–5 mm, with pearly / waxy surface and characteristic central umbilication.
- Common sites — face, trunk, axillae, antecubital fossae in children; genital / perineal in adults.
- Children — usually self-limiting; 50–70% resolve within a year.
- Immunosuppressed adults — extensive, large (5–20 mm), persistent lesions; "giant molluscum" with HIV.
- Surrounding eczema (BOTE — beginning of the end) — sign of immune recognition before resolution.
- "Molluscum dermatitis" — eczematous patches around lesions in some patients.
Dermoscopy
- Pathognomonic appearance — central polylobular structureless yellow-white area (the molluscum body) surrounded by crown-like vessels not crossing the centre.
- Differs from BCC (arborising vessels cross), sebaceous hyperplasia (yellow lobules without crown), milia (no central umbilication).
Differential
- Sebaceous hyperplasia — older adult; yellow lobules; non-resolving.
- BCC — single, pearly, telangiectasia; slow growth over years.
- Milia — superficial, white, no central umbilication.
- Trichoepithelioma — firm; multiple in Brooke-Spiegler.
- Fordyce spots — yellow, smaller, on mucosae.
- Pearly penile papules — coronal, symmetric.
- Giant molluscum in HIV — cryptococcosis, histoplasmosis, penicilliosis can mimic; biopsy if any doubt.
Management
- Observation — most children resolve within 6–18 months without treatment.
- Cryotherapy with liquid nitrogen — usually preferred; one freeze-thaw cycle to each lesion every 2–3 weeks.
- Curettage — quick, definitive; topical anaesthetic (EMLA / Ametop) in children.
- Cantharidin 0.7% — applied in office; well-tolerated in children.
- Topical agents — imiquimod 5%, salicylic acid, potassium hydroxide.
- Immunosuppressed adults — optimise immunosuppression where possible (HIV ART, ICI continuation balanced against burden); systemic cidofovir for refractory.
- Counsel parents — contagious; avoid sharing towels / baths with siblings; usually self-limiting.
- HIV-positive adults with extensive MC — check CD4 count and optimise ART.
References
- Olsen JR et al. Time to resolution and the effect of clinical features on resolution of molluscum contagiosum. Pediatr Dermatol; 2015.
- NICE Clinical Knowledge Summary. Molluscum contagiosum. NICE CKS topic, accessed 18 May 2026.
Spot a correction?
If any clinical statement, citation or link on this page needs updating, please email admin@skinoncology.net with the page name, the proposed correction and the supporting source.