- Clinical science
Molluscum contagiosum is a common localized skin infection caused by the molluscum contagiosum virus that often occurs on the trunk, face and genitalia. It is more common in childhood as well as early adolescence, particularly in males, and is usually transmitted at this age via skin contact and autoinoculation. In adults, it is considered a sexually transmitted infection. Lesions appear as smooth, dome-shaped papules with central umbilication. In healthy patients, molluscum contagiosum is generally self-limiting and heals spontaneously after several months. However, in immunosuppressed individuals, lesions can be very large, widespread, and persistent. If treatment is indicated (e.g., for sexually transmitted molluscum contagiosum), cryotherapy with liquid nitrogen is usually the first treatment option.
- Sex: ♂ > ♀
- Age: most common in childhood (peak incidence < 5 years of age) and early adolescence
Epidemiological data refers to the US, unless otherwise specified.
- Pathogen:: a DNA poxvirus (molluscum contagiosum virus)
- Direct skin contact (contact sports, sexually transmitted in sexually active adolescents and adults)
- Autoinoculation (scratching or touching lesion, e.g., while shaving)
- Fomites (e.g., on bath sponges/towels)
- Risk factors: immunosuppression , active atopic dermatitis (in children) , hot and humid climates, crowded living conditions
Suspect AIDS if large, persistent, widespread lesions appear on an adult!
- Incubation period: 2–6 weeks
- Physical examination: single or multiple lesions in healthy patients; especially widespread in immunocompromised patients
- Predilection sites:
- Localized to the epidermis
- H&E-stained sections demonstrate:
- Spontaneous remission usually happens within 6–9 months (thus treatment often unnecessary).
- Consider treatment for sexually transmitted cases, immunocompromised individuals, and/or to reduce autoinoculation or transmission.
- Cryotherapy; is often the first-line treatment for adolescents and adults as it is better tolerated than in children.
- Topical cantharidin
- Topical imiquimod may be used to successfully treat immunocompromised patients with refractory disease, along with antiretrovirals in HIV-positive patients.
- Secondary bacterial infections
We list the most important complications. The selection is not exhaustive.