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).
When treatment has resulted in the elimination of all bumps, the infection has been effectively cured and will not reappear unless the person is reinfected. Medications
For mild cases, over-the-counter wart medicines, such as salicylic acid may shorten infection duration. Daily topical application of tretinoin cream may also trigger resolution.Studies have found cantharidin to be an effective and safe treatment for removing molluscum contagiosum. This medication is usually well tolerated though mild side effects such as pain or blistering are common. There is no high-quality evidence for cimetidine. However, oral cimetidine has been used as an alternative treatment for the pediatric population as it is generally well tolerated and less invasive. Imiquimod
Imiquimod is a form of immunotherapy initially proposed as a treatment for molluscum based on promising results in small case series and clinical trials. However, two large randomized controlled trials, specifically requested by the U.S. Food and Drug Administration under the Best Pharmaceuticals for Children Act both demonstrated that imiquimod cream applied three times per week was no more effective than placebo cream for treating molluscum after 18 weeks of treatment in a total of 702 children aged 2–12 years. In 2007, results from those trials—which remain unpublished—were incorporated into FDA-approved prescribing information for imiquimod, which states: "Limitations of Use: Efficacy was not demonstrated for molluscum contagiosum in children aged 2–12." In 2007, the FDA also updated imiquimods label concerning safety issues raised in the two large trials and an FDA-requested pharmacokinetic study (the latter of which was published).