Molluscum Contagiosum

Molluscum contagiosum is a common viral infection that causes small bumps on the skin.

Molluscum most often occurs in healthy children. The molluscum virus can be spread to other people by direct skin-to-skin contact with the bumps, and to other areas of the patients’ own skin (“auto-innoculation”) by scratching or rubbing. It can also be spread by contact with an object (eg, towel, gym mat, razor) that gets virus on it by rubbing the bumps. Molluscum that develops in teenagers and adults may be due to sexual activity. Molluscum virus only affects the surface of the body and never spreads internally.

Molluscum bumps usually appear 2 to 6 weeks after viral exposure. The condition lasts for several months to a few years, with an average of about 1 year. During this time, some bumps may disappear on their own, and new ones can develop.

Molluscum lesions begin as dome-shaped, shiny bumps with a central dimple or whitish “core.” They are pink to skin-colored, and pinhead- to pencil eraser–sized. Molluscum may occur anywhere on the skin except the palms and soles. Common sites are the neck, armpits, sides of the chest, thighs, buttocks, genitals, and face. The number of bumps ranges from 1 to dozens, and they are often grouped together.

Skin around the molluscum may become pink, rough, and itchy. This eczema-like reaction can lead to scratching, which can lead to viral spread. The molluscum bumps themselves may become red and swollen, sometimes forming pus-filled pimples. This is usually a good sign that the immune system is fighting the virus and starting to clear the infection. When molluscum bumps go away, they may leave pink-purple or white spots that fade over time.

Doctors can typically recognize molluscum by looking at the skin. Occasionally, scraping or biopsy is done to confirm the diagnosis.

Because molluscum clears on its own over months to a few years, treatment is not needed if the bumps are not bothersome. There is no reason to keep children home from day care or school. The vast majority of people with molluscum, even those with many persistent bumps, have normal immune systems. However, patients with immune disorders may have severe infections.

To prevent viral spread:

• Avoid scratching or picking at the bumps.

• If there is an itchy rash or eczema, apply a topical steroid (over-the-counter hydrocortisone or prescription) daily for 1 or 2 weeks.

• Avoid towel sharing and skin-to-skin contact while bathing with siblings.

• Avoid shaving over, or sexual contact, with areas that have molluscum.

If treatment is desired for children, a common in-office therapy is cantharidin (“blister beetle juice”). This is applied to individual bumps and washed off in 2 to 4 hours; fluid-filled blisters then form, and ideally the bumps resolve as the blisters heal. In-office “curettage,” or scraping off the molluscum bumps, and freezing the bumps with liquid nitrogen are more often done in older children, teens, and adults. At-home use of creams that irritate the bumps’ surface is sometimes helpful.

Correction: This article was corrected on October 9, 2019, to clarify the function of skin creams used at home.

Conflict of Interest Disclosures: None reported.