Molluscum contagiosum is an infection caused by a poxvirus (molluscum contagiosum virus). The result of the infection is usually a benign, mild skin disease characterized by lesions (growths) that may appear anywhere on the body. Within 6-12 months, Molluscum contagiosum typically resolves without scarring but may take as long as 4 years.

The lesions, known as Mollusca, are small, raised, and usually white, pink, or flesh-colored with a dimple or pit in the center. They often have a pearly appearance. They’re usually smooth and firm. In most people, the lesions range from about the size of a pinhead to as large as a pencil eraser (2 to 5 millimeters in diameter). They may become itchy, sore, red, and/or swollen.

Mollusca may occur anywhere on the body including the face, neck, arms, legs, abdomen, and genital area, alone or in groups. The lesions are rarely found on the palms of the hands or the soles of the feet.

Etiology

Molluscum contagiosum is a benign superficial skin disease caused by a poxvirus. It is characterized by small pearly papules with a central depression whose core may be expressed, producing a white cheesy material. The lesions average 2 to 5 mm in size and are usually painless, but may become inflamed, red, and swollen. Molluscum contagiosum is a self-limited infection; the papules usually disappear spontaneously within 6 to 12 months but may take as long as 4 years to resolve.

Clinical Features

The infection is found worldwide but is more common in developing countries and has traditionally been regarded as a pediatric disease. Successful vaccination against smallpox in infancy is not protective. Little has been verified with regard to the incubation period; however, it is estimated to be between 2 weeks and 6 months. Most cases occur in children over 1 year of age, with only one known case reported in an infant (at 7 days post-partum). Atopic dermatitis may be a risk factor for contracting molluscum contagiosum due to the barrier breaks and immune cell dysfunction in atopic skin. In addition, these patients may be more likely to autoinoculate (excoriation of primary lesions and spread to areas of normal skin) new areas of skin because of the underlying pruritus from their atopy.

Patients with HIV/AIDS and other immunocompromising conditions (e.g., solid organ transplant recipients) can develop “giant” lesions (≥15 mm in diameter), larger numbers of lesions, and lesions that are more resistant to standard therapy. The following diseases should be considered in the differential diagnosis of molluscum contagiosum: cryptococcosis, basal cell carcinoma, keratoacanthoma, histoplasmosis, coccidioidomycosis, and verruca vulgaris. For genital lesions, condyloma acuminata and vaginal syringomas should be considered.

Molluscum contagiosum lesions have recently come to be classified in one of three ways: the commonly seen skin lesions found largely on the faces, trunks, and limbs of children; the sexually transmitted lesions found on the abdomen, inner thighs, and genitals of sexually active adults; and the diffuse and recalcitrant eruptions of patients with AIDS or other immunosuppressive disorders.

The virus that causes molluscum spreads from direct person-to-person physical contact and through contaminated fomites. Fomites are inanimate objects that can become contaminated with virus; in the instance of molluscum contagiosum this can include linens such as clothing and towels, bathing sponges, pool equipment, and toys. Although the virus might be spread by sharing swimming pools, baths, saunas, or other wet and warm environments, this has not been proven. Researchers who have investigated this idea think it is more likely the virus is spread by sharing towels and other items around a pool or sauna than through water.

Someone with molluscum can spread it to other parts of their body by touching or scratching a lesion and then touching their body somewhere else. This is called autoinoculation. Shaving and electrolysis can also spread mollusca to other parts of the body.

Molluscum can spread from one person to another by sexual contact. Many, but not all, cases of molluscum in adults are caused by sexual contact.

Conflicting reports make it unclear whether the disease may be spread by simple contact with seemingly intact lesions or if the breaking of a lesion and the subsequent transferring of core material is necessary to spread the virus.

The molluscum contagiosum virus remains in the top layer of skin (epidermis) and does not circulate throughout the body; therefore, it cannot spread through coughing or sneezing.

Since the virus lives only in the top layer of skin, once the lesions are gone the virus is gone and you cannot spread it to others. Molluscum contagiosum is not like herpes viruses, which can remain dormant (“sleeping”) in your body for long periods and then reappear.

Who is at risk for infection?

Molluscum contagiosum is common enough that you should not be surprised if you see someone with it or if someone in your family becomes infected. Although not limited to children, it is most common in children 1 to 10 years of age.

People at increased risk for getting the disease include:

• People with weakened immune systems (i.e., HIV-infected persons or persons being treated for cancer) are at higher risk for getting molluscum contagiosum. Their growths may look different, be larger, and be more difficult to treat.
• Atopic dermatitis may also be a risk factor for getting molluscum contagiosum due to frequent breaks in the skin. People with this condition also may be more likely to spread molluscum contagiousm to other parts of their body for the same reason.
• People who live in warm, humid climates where living conditions are crowded.

In addition, there is evidence that molluscum infections have been on the rise in the United States since 1966, but these infections are not routinely monitored because they are seldom serious and routinely disappear without treatment.

What are the treatment options?

Because molluscum contagiosum is self-limited in healthy individuals, treatment may be unnecessary. Nonetheless, issues such as lesion visibility, underlying atopic disease, and the desire to prevent transmission may prompt therapy.

Treatment for molluscum is usually recommended if lesions are in the genital area (on or near the penis, vulva, vagina, or anus). If lesions are found in this area it is a good idea to visit your healthcare provider as there is a possibility that you may have another disease spread by sexual contact.

Be aware that some treatments available through the internet may not be effective and may even be harmful.

Physical removal

Physical removal of lesions may include cryotherapy (freezing the lesion with liquid nitrogen), curettage (the piercing of the core and scraping of caseous or cheesy material), and laser therapy. These options are rapid and require a trained health care provider, may require local anesthesia, and can result in post-procedural pain, irritation, and scarring.

It is not a good idea to try and remove lesions or the fluid inside of lesions yourself. By removing lesions or lesion fluid by yourself you may unintentionally autoinoculate other parts of the body or risk spreading it to others. By scratching or scraping the skin you could cause a bacterial infection.

Oral therapy

Gradual removal of lesions may be achieved by oral therapy. This technique is often desirable for pediatric patients because it is generally less painful and may be performed by parents at home in a less threatening environment. Oral cimetidine has been used as an alternative treatment for small children who are either afraid of the pain associated with cryotherapy, curettage, and laser therapy or because the possibility of scarring is to be avoided. While cimetidine is safe, painless, and well tolerated, facial mollusca do not respond as well as lesions elsewhere on the body.

Topical therapy

Podophyllotoxin cream (0.5%) is reliable as a home therapy for men but is not recommended for pregnant women because of presumed toxicity to the fetus. Each lesion must be treated individually as the therapeutic effect is localized. Other options for topical therapy include iodine and salicylic acid, potassium hydroxide, tretinoin, cantharidin (a blistering agent usually applied in an office setting), and imiquimod (T cell modifier). Imiquimod has not been proven effective for the treatment of molluscum contagiosum in children and is not recommended for children due to possible adverse events. These treatments must be prescribed by a health care professional.

Therapy for immunocompromised persons

Most therapies are effective in immunocompetent patients; however, patients with HIV/AIDS or other immunosuppressing conditions often do not respond to traditional treatments. In addition, these treatments are largely ineffective in achieving long-term control in HIV patients.

Low CD4 cell counts have been linked to widespread facial mollusca and therefore have become a marker for severe HIV disease. Thus far, therapies targeted at boosting the immune system have proven the most effective therapy for molluscum contagiosum in immunocompromised persons. In extreme cases, intralesional interferon has been used to treat facial lesions in these patients. However, the severe and unpleasant side effects of interferon, such as influenza-like symptoms, site tenderness, depression, and lethargy, make it a less-than-desirable treatment. Furthermore, interferon therapy proved most effective in otherwise healthy persons. Radiation therapy is also of little benefit.

If you’re bothered by bumps on your skin, don’t try to diagnose yourself or treat your condition with products that haven’t been approved by the U.S. Food and Drug Administration. Instead, visit a health care professional for a proper diagnosis and to make a treatment plan.

One common condition that some people try to self-diagnose and treat is molluscum contagiosum, a skin infection caused by a virus. But by doing so, you run the risk of delaying the diagnosis and treatment of a potentially more serious condition. And you might do more harm than good.

There is only one FDA-approved treatment for molluscum, called Ycanth (cantharidin), which must be administered by a health care professional. The FDA has not approved any nonprescription products to treat molluscum.

Symptoms and Causes of Molluscum

Molluscum, also called water warts, is a common, benign, viral infection that can cause white, pink, or flesh-colored bumps. These growths can happen alone or in groups almost anywhere on the skin, including the face, neck, arms, legs, abdomen, and genital area. The bumps are rarely on the palms of the hands or soles of the feet.

Sometimes the bumps itch and get irritated. People with a weakened immune system may have larger or more bumps. If you don’t have the condition evaluated by a health care professional, you won’t know if the bumps are molluscum or a symptom of another skin ailment.

Molluscum is an infection common in children, although teens and adults can also get it. Molluscum is transmitted by skin-to-skin contact, including sexual contact, and can be transmitted by sharing clothes or infected objects such as sports equipment. Good hygiene (cleanliness) and avoiding direct contact with bumps are the best ways to avoid getting molluscum. This includes washing your hands, keeping hands, clothes, and equipment clean, and covering bumps if you have them.

Molluscum eventually goes away on its own without treatment, typically within six to 12 months, but sometimes up to five years.

If you have molluscum, a skin doctor (dermatologist) or other health care professional can evaluate your symptoms and recommend ways to manage your condition.

Safely Treating Molluscum

The FDA has approved Ycanth (cantharidin) for the topical (used on the skin) treatment of molluscum in adults and children ages 2 and older. Ycanth, the first FDA-approved treatment for molluscum, is administered to patients only by health care professionals. Providers apply a single application of Ycanth on the areas of patients’ skin with molluscum bumps every three weeks as needed.

Do not purchase or use nonprescription (over-the-counter, or OTC) products that claim to treat molluscum, even if the companies make statements that suggest their product may have been reviewed or is endorsed by the FDA. Some companies may mislead consumers by saying their product is “FDA-approved,” is “FDA registered,” is made in an “FDA-registered facility,” or “complies with FDA Current Good Manufacturing Practices” (or “CGMPs”).

It’s likely that unapproved products marketed to treat molluscum do not do what they claim, and the ingredients in them could cause adverse effects (bad reactions). The FDA has received reports of side effects in children and adults associated with some of these products, including skin reddening, abrasion from skin scratching, and permanent scarring.

Many unapproved products claiming to treat molluscum contain essential oils. Even natural substances, such as essential oils, may cause an allergic reaction or irritate sensitive skin.

How can I keep it from spreading?

The best way to avoid getting molluscum is by following good hygiene habits. Remember that the virus lives only in the skin and once the lesions are gone, the virus is gone and you cannot spread the virus to others.

Wash your hands

There are ways to prevent the spread of molluscum contagiosum. The best way is to follow good hygiene (cleanliness) habits. Keeping your hands clean is the best way to avoid molluscum infection, as well as many other infections. Hand washing removes germs that may have been picked up from other people or from surfaces that have germs on them. See the Handwashing site for more information.

Don’t scratch or pick at molluscum lesions

It is important not to touch, pick, or scratch skin that has lesions, that includes not only your own skin but anyone else’s. Picking and scratching can spread the virus to other parts of the body and makes it easier to spread the disease to other people too.

Keep molluscum lesions covered

It is important to keep the area with molluscum lesions clean and covered with clothing or a bandage so that others do not touch the lesions and become infected. Do remember to keep the affected skin clean and dry.

Any time there is no risk of others coming into contact with your skin, such as at night when you sleep, uncover the lesions to help keep your skin healthy.

Be careful during sports activities

Do not share towels, clothing, or other personal items.

People with molluscum should not take part in contact sports like wrestling, basketball, and football unless all lesions can be covered by clothing or bandages.

Activities that use shared gear like helmets, baseball gloves and balls should also be avoided unless all lesions can be covered.

Swimming should also be avoided unless all lesions can be covered by watertight bandages. Personal items such as towels, goggles, and swim suits should not be shared. Other items and equipment such as kick boards and water toys should be used only when all lesions are covered by clothing or watertight bandages.

Other ways to avoid sharing your infection

Do not shave or have electrolysis on areas with lesions.

Don’t share personal items such as unwashed clothes, hair brushes, wrist watches, and bar soap with others.

If you have lesions on or near the penis, vulva, vagina, or anus, avoid sexual activities until you see a health care provider.

What are the long-term effects?

Recovery from one molluscum infection does not prevent future infections. Molluscum contagiosum is not like herpes viruses which can remain dormant (“sleeping”) in your body for long periods of time and then reappear. If you get new molluscum contagiosum lesions after you are cured, it means you have come in contact with an infected person or object again.

Complications

The lesions caused by molluscum are usually benign and resolve without scarring. However scratching at the lesion, or using scraping and scooping to remove the lesion, can cause scarring. For this reason, physically removing the lesion is not often recommended in otherwise healthy individuals.

The most common complication is a secondary infection caused by bacteria. Secondary infections may be a significant problem in immunocompromised patients, such as those with HIV/AIDS or those taking immunosuppressing drug therapies. In these cases, treatment to prevent further spread of the infection is recommended.

Swimming Pools

Some investigations report that spread of molluscum contagiosum is increased in swimming pools. However, it has not been proved how or under what circumstances swimming pools might increase spread of the virus. Activities related to swimming might be the cause. For example, the virus might spread from one person to another if they share a towel or toys. More research is needed to understand if and for how long the molluscum virus can live in swimming pool water and if such water can infect swimmers.

Day Care Centers and Schools

If you notice bumps on a child’s skin, it is reasonable to inform the child’s parents and to request a doctor’s note. Only a healthcare professional can diagnose molluscum contagiosum because there are many other causes of growths on the skin, both infectious and non-infectious.

Work

Although there has been only one reported case of healthcare provider-to-patient transmission of molluscum contagiosum, if an employee who comes in physical contact with clients regularly, such as an aesthetician or health care provider, is diagnosed with molluscum contagiosum by a health care professional, it would be reasonable to require that he/she cover visible lesions with a watertight dressing while at work. Otherwise, no special precautions are needed.

There is no reason to keep a child with molluscum infection home from day care or school.

If you notice lesions on a child’s skin, it is reasonable to inform the child’s parents and to request a doctor’s note. Only a healthcare professional can diagnose molluscum contagiosum because there are many other causes of growths on the skin, both infectious and non-infectious.

Lesions not covered by clothing should be covered with a watertight bandage. Change the bandage daily or when obviously soiled.

If a child with lesions in the underwear/diaper area needs assistance going to the bathroom or needs diaper changes, then lesions in this area should be bandaged too if possible.

Covering the lesions will protect other children and adults from getting molluscum and will also keep the child from touching and scratching the lesions, which could spread the infection to other parts of his/her body or cause secondary (bacterial) infections.

Parents and others often ask if molluscum virus can spread in swimming pools. There is also concern that it can spread by sharing swimming equipment, pool toys, or towels.

Some investigations report that spread of molluscum contagiosum is increased in swimming pools. However, it has not been proved how or under what circumstances swimming pools might increase spread of the virus. Activities related to swimming might be the cause. For example, the virus might spread from one person to another if they share a towel or toys. More research is needed to understand if and for how long the molluscum virus can live in swimming pool water and if such water can infect swimmers.

Open sores and breaks in the skin can become infected by many different germs. Therefore, people with open sores or breaks from any cause should not go into swimming pools.

If a person with molluscum is going swimming, they should:

• Cover all visible lesions with watertight bandages
• Dispose of all used bandages at home
• Not share towels, kick boards, other equipment, or toys

Although there has been only one reported case of healthcare provider-to-patient transmission of molluscum contagiosum, if an employee who comes in physical contact with clients regularly, such as an aesthetician or healthcare provider, is diagnosed with molluscum contagiosum by a healthcare professional, it would be reasonable to require that he/she cover visible lesions with a watertight dressing while at work. Otherwise, no special precautions are needed.

Other precautions can prevent or reduce spread to uninfected people:

• Frequent and correct hand hygiene practices. For handwashing tips and information, see the Clean Hands Saves Lives site.
• Requiring notation of molluscum contagiosum on examinations requested for—
  • Employment
    • Recommended only for employees with regular physical contact with clients (e.g., aestheticians, health care professionals, day care employees) who are normally required to have skin examinations during pre-employment physicals.
  • Camp
  • Sports physicals
• Recommending that all visible lesions be covered by a watertight dressing, if molluscum contagiosum is diagnosed by a healthcare professional during a physical examination.
• Routinely disinfecting shared equipment (e.g., kick boards, wrestling mats). The molluscum contagiosum virus is not particularly difficult to kill and usual sanitation procedures should be sufficient.