This infection is caused by a poxvirus.
The bumps can appear on many parts of the body but usually are not itchy or painful.
The diagnosis is typically based on the appearance of the bumps.
Bumps that do not go away by themselves can be treated with creams or can be removed by freezing, burning, and/or cutting.
The bumps are usually less than 1/4 inch (about 0.2 to 0.5 centimeters) in diameter, shaped like a dome, and have a tiny dimple in the center. The virus that causes molluscum is contagious. It spreads by direct contact with skin (for example, wrestling) or objects such as towels or sponges that have been touched by an infected person. The virus can also be spread in water such as in pools, baths, or saunas. This infection is common among children. Genital lesions are often transmitted sexually in adults. Infection can be more widespread among people who have a weakened immune system such as those with HIV/AIDS or who use corticosteroids by mouth or receive cancer chemotherapy.
Molluscum contagiosum can infect any part of the skin except the palms of the hands and soles of the feet. The infection is typically chronic.
In children, the bumps occur most commonly on the face, trunk, arms, and legs. In adults, the bumps occur most commonly on the penis, vulva, or in the pubic area. The bumps usually are not itchy or painful and may be discovered only coincidentally during a physical examination. However, the bumps can become very inflamed (resembling a boil) and itchy as the body fights off the virus. This inflammation may indicate that the bumps will soon disappear.
Most bumps disappear spontaneously in 1 to 2 years, but they can remain for 2 to 3 years. People with bumps in the groin that were presumably acquired sexually should be treated to prevent spread of the infection. Otherwise, no treatment of molluscum contagiosum is needed unless the growths are disfiguring or otherwise bothersome.
Doctors apply or prescribe trichloroacetic acid, podophyllotoxin (in adults), tretinoin, tazarotene, or cantharidin to the bumps. These creams are applied for weeks or months.
The bumps also can be treated by freezing (cryotherapy), burning with a laser or electric current, or removing their core with a needle or sharp scraping instrument (curette).
Dermatologists often use combination therapy such as liquid nitrogen or cantharidin in the office and give people a retinoid cream to use at home. This form of therapy is typically successful, but in some people the bumps often take 1 to 2 months to go away.
Other treatments include injection of Candida antigen into a bump and photodynamic therapy. Candida antigens are proteins that come from the Candida yeast. When injected into the bump, they cause an immune response that fights against the virus. Similarly, interferons are proteins that trigger immune cells to attack the virus. In photodynamic therapy, a chemical preparation is applied to the skin and then artificial light is applied to the bumps. The light activates the chemical to produce a form of oxygen that kills the virus causing the bumps.
Children do not need to be excluded from school or day care. However, their bumps should be covered to reduce the risk of spread to others.