Genital Molluscum Contagiosum

Genital molluscum contagiosum is a self limiting poxvirus infection of the skin producing umbilicated papules in the genital, pubic, lower abdominal and inner thigh areas. In adults it is transmitted sexually; in children it spreads by skin contact.

• Spread by direct skin contact, fomites and autoinoculation.
• Extensive, giant or persistent lesions occur in HIV infection with low CD4 counts.
• Usually resolves within 6 to 12 months in immunocompetent people; may take years.

Multiple 2 to 5 mm skin coloured, dome shaped, pearly papules with central umbilication, in clusters on the pubis, genitalia, thighs and lower abdomen.

• Usually asymptomatic; may itch; inflamed lesions appear red and tender as the immune response begins.
• Differential diagnosis: genital warts, herpes simplex, folliculitis, syphilis (condylomata lata), cryptococcosis, histoplasmosis, talaromycosis (in HIV), basal cell carcinoma, epidermoid cyst, scabies nodules, sebaceous hyperplasia.
• Complications: secondary bacterial infection, eczema around lesions (molluscum dermatitis), scarring, spread to partners, giant molluscum in HIV, ocular involvement near eyelids, persistence in immunosuppression.

Clinical; dermoscopy shows central pore with polylobular structures.

• Expressed core microscopy (Giemsa stain) or biopsy for atypical or giant lesions to exclude cryptococcosis and talaromycosis.
• Screen for other sexually transmitted infections: HIV, syphilis serology, gonorrhoea and chlamydia testing, hepatitis B; offer partner notification.
• In children with genital lesions, assess for sexual abuse sensitively.

Treat to reduce spread and symptoms; observation is acceptable in immunocompetent adults, but treatment is advised for genital disease to limit transmission.

• Supportive: avoid scratching and shaving over lesions, avoid sexual contact until lesions resolve or are treated, do not share towels, hygiene, cover lesions.
• Pharmacological: potassium hydroxide 5 to 10 percent solution applied to each lesion twice daily until inflamed; cantharidin 0.7 percent applied in clinic and washed off after 2 to 6 hours (where available); podophyllotoxin 0.5 percent solution or 0.15 percent cream twice daily for 3 days, repeated weekly for up to 4 weeks (not in pregnancy); imiquimod 5 percent cream three times weekly (limited efficacy). Topical cidofovir 1 to 3 percent compounded cream in resistant HIV associated disease.
• Procedures: curettage, cryotherapy for 5 to 10 seconds, expression of core with forceps. Use topical anaesthetic (lidocaine 2.5 percent with prilocaine 2.5 percent cream) in children.
• Special groups: pregnancy, curettage or cryotherapy, avoid podophyllotoxin and cidofovir; HIV, start or optimise antiretroviral therapy, which is the most effective measure, and treat lesions; children, avoid painful destruction and use topical agents; eczema, treat dermatitis with emollient and mild topical corticosteroid.
• Red flags: giant or ulcerated lesions, lesions not umbilicated, immunosuppression, extensive facial lesions, eyelid involvement, systemic features suggesting disseminated fungal infection, genital lesions in a young child.
• Follow-up: review at 4 weeks; test for other sexually transmitted infections; partner notification; repeat HIV test in the window period if initially negative and at risk.