Molluscum contagiosum (MC), sometimes called water warts, is a viral infection of the skin that results in small raised pink lesions with a dimple in the center. They may become itchy or sore, and occur singularly or in groups. Any area of the skin may be affected, with abdomen, legs, arms, neck, genital area, and face being the most common. Onset of the lesions is around seven weeks after infection. They usually go away within a year without scarring.

The infection is caused by a poxvirus called the molluscum contagiosum virus (MCV). The virus is spread either by direct contact, including sexual activity, or via contaminated objects such as towels. The condition can also be spread to other areas of the body by the person themselves. Risk factors include a weak immune system, atopic dermatitis, and crowded living conditions. Following one infection, it is possible to get re-infected. Diagnosis is typically based on the appearance of the lesions.

Prevention includes hand washing and not sharing personal items. While treatment is not necessary, some may wish to have the lesions removed for cosmetic reasons or to prevent spread. Removal may occur with freezing, laser therapy, or opening up the lesion and scraping the inside. Scraping the lesion can, however, result in scarring. The oral medication cimetidine, or podophyllotoxin cream applied to the skin, may also be used for treatment.

Approximately 122 million people globally were affected by molluscum contagiosum as of 2010 (1.8% of the population). It is more common in children between the ages of one and ten years old. The condition has become more common in the United States since 1966. But having an infection is not a reason to keep a child out of school or daycare.