Molluscum contagiosum (mo-LUS-kum kun-tay-jee-OH-sum) is a relatively common viral infection of the skin that results in round, firm, painless bumps ranging in size from a pinhead to a pencil eraser. If the bumps are scratched or injured, the infection can spread to surrounding skin. Molluscum contagiosum also spreads through person-to-person contact and contact with infected objects.

Though most common in children, molluscum contagiosum can affect adults as well — particularly those with weakened immune systems. In adults with an otherwise normal immune system, molluscum contagiosum involving the genitals is considered a sexually transmitted infection.

The bumps associated with molluscum contagiosum usually disappear within a year without treatment but doctor-assisted removal is also an option.

Signs and symptoms of molluscum contagiosum include bumps on the skin that:

• Are raised, round and flesh colored
• Are small — typically under about 1/4 inch (smaller than 6 millimeters) in diameter
• Characteristically have a small indentation (umbilication) or dot at the top near the center
• Can become red and inflamed
• May be itchy
• Can be easily removed by scratching or rubbing, which can spread the virus to adjacent skin
• Usually appear on the face, neck, armpits, arms and tops of the hands in children
• May be seen on the genitals, lower abdomen and inner upper thighs in adults if the infection was sexually transmitted

When to see a doctor

If you suspect you or your child has molluscum contagiosum, consult your primary care doctor.

The virus that causes molluscum contagiosum spreads easily through:

• Skin-to-skin contact
• Contact with contaminated objects, such as towels
• Sexual contact with an affected partner
• Scratching or rubbing the bumps, which spreads the virus to nearby skin

It's not clear if the molluscum contagiosum virus can spread in the chlorinated water found in swimming pools. Experts suspect that it's more likely that swimmers transmit the virus through shared use of towels; equipment, such as kickboards; or skin contact.

More widespread molluscum contagiosis infections may occur in people with weakened immune systems.

The bumps and the skin around them may become red and inflamed. This is thought to be an immune response to the infection. If scratched, these bumps can become infected. If lesions appear on the eyelids, pink eye (conjunctivitis) can develop.

To help prevent the spread of the virus:

• Wash your hands. Keeping your hands clean can help prevent spreading the virus.
• Avoid touching the bumps. Shaving over the infected areas also can spread the virus.
• Don't share personal items. This includes clothing, towels, hairbrushes or other personal items. Refrain from borrowing these items from others as well.
• Avoid sexual contact. If you have molluscum contagiosum on or near your genitals, don't have sex until the bumps are treated and have completely disappeared.
• Cover the bumps. Cover the bumps with clothing when around others, to prevent direct contact. When swimming, cover the bumps with a watertight bandage.

Your doctor usually can diagnose molluscum contagiosum just by looking at it. If there's any doubt, he or she may take skin scrapings from the infected area and view them under a microscope.

Molluscum contagiosum usually gets better without treatment in six to 12 months. However, it's possible to continue developing bumps for up to five years. Once all of your bumps are gone, you're no longer contagious.

Doctors may recommend that the lesions be removed before they disappear on their own, particularly in adults, because they are so contagious. Treatments for molluscum contagiosum can be painful, so an anesthetic might be administered beforehand to lessen discomfort. Sometimes a combination of treatments may be used.

Options include:

• Scraping
• Freezing (cryotherapy)
• A medicine that causes blisters (cantharidin), which lift off the bumps

You'll likely start by visiting your or your child's primary care practitioner. However, in some cases when you call to set up an appointment, you may be referred immediately to a doctor who specializes in treating skin conditions (dermatologist).

Because appointments can be brief, and because there's often a lot of ground to cover, it's a good idea to be well-prepared for your appointment. Here's some information to help you get ready for your appointment, and know what to expect from your doctor.

What you can do

Before your appointment, write a list that answers the following questions:

• What symptoms are you experiencing?
• What, if anything, seems to improve your symptoms?
• What, if anything, appears to worsen your symptoms?
• What medications and supplements do you take on a regular basis?

What to expect from your doctor

Your doctor is likely to ask you a number of questions. Being ready to answer them may reserve time to go over any points you want to spend more time on. Your doctor may ask:

• When did you first begin experiencing symptoms?
• Have your symptoms been continuous or occasional?
• Have you had similar lesions in the past?
• Has anyone close to you had similar lesions?