Molluscum contagiosum (MC) is a common, self-limited poxvirus infection presenting as dome-shaped, umbilicated papules. It spreads via skin-to-skin contact, fomites, and autoinoculation. Disease is more frequent in children, sexually active adults (genital/perineal), swimmers/wrestlers, and the immunosuppressed (numerous, atypical, giant lesions). While spontaneous resolution within 6–18 months is typical, treatment is often pursued for symptom relief, cosmetic reasons, reduction of transmission, and to prevent dermatitis or scarring from scratching. Options include topical agents (cantharidin 0.7% device-approved formulations), curettage, cryotherapy, potassium hydroxide, and immunomodulators; approach is individualized by age, site, tolerance, and skin type.
Epidemiology and Risk Factors
- Common in children 2–10 years; outbreaks in daycare/sports (wrestling, swimming).
- Adults: sexually transmitted in genital/perigenital regions.
- Risk factors: atopic dermatitis (barrier defect, koebnerization), immunosuppression (HIV, transplant), occlusive shaving/waxing.
Clinical Features
- Firm, shiny, 2–5 mm papules with central dell; white/pearly core.
- Distribution: trunk, flexures, extremities in kids; genital/perineal, lower abdomen, inner thighs in adults.
- Inflammation indicates immune recognition (molluscum dermatitis, “beginning of the end”); lesions may become erythematous and crusted before clearing.
Differential Diagnosis
- Verruca vulgaris, basal cell carcinoma (solitary pearly papule in adults), folliculitis, milia, varicella in clusters, condyloma acuminata (genital warts).
Diagnosis
- Clinical. Dermoscopy: central polylobular white/yellow amorphous structures with peripheral vessels.
- If uncertain or atypical (giant, ulcerated), consider biopsy.
Management
- Observation
- Reasonable in healthy children; natural resolution expected. Educate about course and avoidance of scratching/sharing towels.
- Office-based destructive therapies
- Curettage: immediate clearance; may need topical anesthetic; risk of PIH/scarring; often preferred for limited lesions in older children/adults.
- Cryotherapy: 1–2 freeze–thaw cycles; repeat every 2–3 weeks as needed; PIH risk in darker skin.
- Cantharidin 0.7% (FDA-cleared device formulations): painless application; blistering in 24–48 hours; wash-off timing per product; effective with minimal scarring when used properly; avoid face/genitals/intertriginous areas in young children unless experienced.
- Topical/at-home options
- Potassium hydroxide 5–10% solution applied qd–bid until mild inflammation.
- Tretinoin 0.025–0.05% cream/gel nightly; slow but useful in sensitive sites.
- Benzoyl peroxide or salicylic acid spot treatment; variable efficacy.
- Immunomodulators: imiquimod has not shown consistent benefit in RCTs for children and often irritates—generally not recommended.
- Newer keratolytic combinations or nitric oxide–releasing agents have emerging evidence in some regions.
- Special scenarios
- Atopic dermatitis: treat eczematous halo with low-potency topical steroids or tacrolimus to reduce scratching/autoinoculation; continue gentle skincare.
- Genital MC: consider STI screening/counseling; use non-scarring modalities (curettage, cautious cryo).
- Immunosuppressed/HIV: numerous or giant lesions may require more aggressive therapy; optimize antiretroviral therapy; consider curettage, cantharidin, cryo; cidofovir (topical/intralesional) has case-based evidence for refractory disease.
- Prevention and counseling
- Do not share towels/razors; cover lesions during contact sports; avoid shaving over lesions.
- Expect transient post-treatment PIH or hypopigmentation; scarring risk is lower with cantharidin and careful curettage.
References (recent guidelines and key reviews)
- Pediatric and dermatologic society guidance on MC management, 2021–2024.
- RCTs/meta-analyses of cantharidin and other topicals, 2021–2024.
- MC in atopic dermatitis and immunosuppressed hosts reviews, 2022–2024.