International Academy of Cosmetic Dermatology
Molluscum contagiosum (MC) is a common viral disease, caused by a poxvirus distinct from other poxviruses (large 200 by 300 nm DNA virus), which infects the skin and mucous membranes in both children and adults. The characteristic lesion is a discrete pearly dome shaped papule, which look like M&M candies pasted on the skin. They often appear in clusters, being a few mm (about ½ inch) in diameter with central umbilication. The skin keeps the group of globules on the skin. Histologically, there is hypertrophied and hyperplastic epidermis. Above the basal layer, there are lobules of epidermal cells containing inclusion bodies.
In children, MCs are found on the arms, trunk, and legs. In adults, MCs affect the face and chest, often not the genitals, although it is often sexually transmitted. In immune-suppressed patients, especially with HIV infection, MC may be extensive. Giant MC-like lesions, frequently confused with common warts, may be seen with several HIV-related opportunistic infections such as cryptococcosis, histoplasmosis, and penicillosis.
MCs usually disappear within a two-year period. Treatment involves destruction of the molluscum bodies by interfering with the epidermis. Each physician has a chosen method of eliminating this viral infection: applying keratolytics or imiquimod cream (Aldara®), curettage and cautery, or cryotherapy. In HIV infected patients they often seem to go spontaneously once the immune status is improved with highly active antiretroviral therapy (HAART). Because MCs are innocuous, children need not be forced to have treatment.
Michael Waugh, MB, FRCP