Etiology and Transmission of Molluscum Contagiosum
Molluscum contagiosum is caused by a double-stranded DNA poxvirus (molluscum contagiosum virus, MCV) from the Poxviridae family, transmitted primarily through direct skin-to-skin contact, fomites (shared towels, clothing, equipment), contaminated water in communal settings (pools, hot tubs), sexual contact in adults, and autoinoculation. 1, 2
Causative Agent
- The molluscum contagiosum virus (MCV) is a double-stranded DNA virus belonging to the Poxviridae family that replicates specifically in the human epidermis 2, 3, 4
- The virus remains infectious throughout the entire clinical course of lesions, which typically persist for 6-12 months but can last up to 4-5 years without treatment 1, 5
Modes of Transmission
Direct Contact Transmission
- Direct skin-to-skin contact with infected individuals is the primary mode of transmission, occurring through both non-sexual contact in children and sexual contact in adults 1, 2
- Autoinoculation through scratching or touching lesions spreads the virus to adjacent skin areas, making it critical to educate patients to avoid manipulating lesions 1, 5
Fomite Transmission
- The virus spreads through sharing contaminated objects including towels, clothing, personal items, and equipment 1, 5, 2
- The American Academy of Pediatrics emphasizes not sharing equipment and towels as essential prevention measures 1
Water-Based Transmission
- Communal water facilities including swimming pools and hot tubs serve as transmission sources, with the American Academy of Pediatrics recommending limiting exposure to pools associated with known outbreaks 1
- Hot tubs present higher transmission risk than standard pools due to warmer water temperatures facilitating viral survival, closer proximity between users, and shared seating surfaces serving as fomites 1
- All molluscum lesions should be covered with waterproof bandages if water exposure is unavoidable 1, 5
Sexual Transmission
- In sexually active adults, transmission occurs through intimate skin contact, with lesions typically appearing on genitalia, pubis, and inner thighs 2, 6
- Genital involvement represents the lowest occurrence site at approximately 3% of cases 6
Prevention Strategies
- Hand hygiene using alcohol-based disinfectant or washing with soap and water is the most important method to prevent transmission of infectious agents 1, 5
- Avoid skin contact with infected individuals and do not share towels, clothing, or personal items 1, 5
- Keep all lesions covered with waterproof bandages during unavoidable water exposure 1, 5
- Return to communal water facilities is appropriate only when all lesions have completely resolved, skin has returned to normal appearance, and no new lesions have appeared for several weeks 1
Special Populations
- In immunocompromised patients (particularly HIV-positive individuals), atypical manifestations occur including giant lesions (10-15mm), disseminated forms, and extensive disease with minimal inflammation 1, 3, 7
- Children aged 1-5 years represent the most commonly affected population, with lesions typically on face, trunk, and extremities rather than genital areas 2, 6