Molluscum Contagiosum: Causes, Symptoms, and Treatment Options

What Is Molluscum Contagiosum?

Molluscum contagiosum is a skin infection caused by the molluscum contagiosum virus (MCV), a type of poxvirus—the same virus family as smallpox, though far less serious. The virus infects only the outer skin cells (keratinocytes) and does not spread to internal organs.

The name comes from Latin: molluscum means “soft,” and contagiosum reflects how easily it spreads. The infection is very common in children aged 2–10 years and is also transmitted between adults through sexual contact.

In people with healthy immune systems, molluscum is a self-limiting infection—meaning the body eventually clears it on its own. However, in people with weakened immune systems (such as those with HIV), the infection can be much harder to control.

Signs and Symptoms

The bumps caused by molluscum contagiosum are quite distinctive. Look for:

• Small, round, raised bumps (papules) that are 2–5 mm in size—about the size of a small pea.
• Pearly white or skin-colored appearance with a shiny surface.
• A characteristic dimple or pit in the center, called umbilication, which may contain a white or yellow cheesy material.
• Bumps typically appear in groups of 10–50, though people with weakened immune systems may have over 100.
• In children, bumps are most common on the face, trunk, and skin folds (armpits, behind the knees).
• In adults, genital and inner thigh areas are most commonly affected when transmitted sexually.

Additional effects to be aware of:

• Molluscum dermatitis: About 30–50% of people develop redness, itching, and flaking around the bumps as the immune system reacts.
• Secondary bacterial infection: Scratching can introduce bacteria, causing 10–15% of cases to become infected with redness, swelling, and pus.

Causes and Risk Factors

The molluscum contagiosum virus spreads through:

• Direct skin-to-skin contact with an infected person.
• Fomites—shared objects such as towels, clothing, pool toys, and sports equipment.
• Sexual contact in adults.
• Scratching and touching existing bumps on your own body can spread them to other areas (autoinoculation).

Factors that increase your risk or severity:

• Atopic dermatitis (eczema): A broken or inflamed skin barrier makes it easier for the virus to enter.
• Weakened immune system: People with HIV (especially with a CD4 cell count below 100) have infection rates of 5–18%, compared to about 0.3% in people with normal immunity.
• Warm, humid climates: Higher prevalence is seen in tropical regions.
• Shared spaces: Schools, swimming pools, locker rooms, and daycare centers are common transmission environments.

The virus is clever at evading the immune system—it produces a protein that blocks the body’s interferon-gamma response, which is why infections can last so long without treatment.

How It’s Diagnosed

A dermatologist can usually diagnose molluscum contagiosum just by looking at the bumps—the central dimple is a hallmark feature that sets it apart from most other skin conditions. Additional tools include:

• Dermoscopy: A handheld magnifying device that allows the doctor to see the central dimple and surrounding yellow-white material more clearly.
• Skin biopsy: Rarely needed, but if the diagnosis is uncertain, a small skin sample will show distinctive large cells called molluscum bodies (or Henderson-Patterson bodies) inside the skin cells—a definitive finding.

Conditions that can look similar include chickenpox, herpes simplex, follicular papules, and sebaceous cysts (small oil-gland cysts). Your dermatologist will distinguish between these based on the appearance and, if needed, testing.

Treatment Options

Treatment is not always required—in healthy children, the bumps often clear on their own in 6–18 months. However, treatment is reasonable to prevent spread, reduce discomfort, and shorten the course of the infection.

Watchful waiting (observation):

• A valid approach for mild, non-spreading molluscum in healthy individuals.
• Risk: the virus may spread to new skin areas or to contacts during the waiting period.

Topical (surface) treatments—applied at home:

• Imiquimod 5% cream (Aldara): Applied 3 times a week for 12–16 weeks. Activates the immune system to fight the virus; clears infection in 60–80% of healthy patients.
• Tretinoin 0.05–0.1% cream: Applied nightly for 8–12 weeks; shown to clear 50–70% of cases.
• Potassium hydroxide 15–20% solution: Applied twice daily to dissolve the bumps chemically; achieves about 60% resolution over 2–3 months.

In-office procedures performed by your dermatologist:

• Cantharidin (Cantharone): A blistering agent applied by the doctor, left on for 4–6 hours, then washed off. Causes the bump to blister and peel away; effective in 60–75% at first application.
• Cryotherapy (liquid nitrogen): Freezing each bump for 10–15 seconds. Multiple treatments spaced 2–4 weeks apart are usually needed.
• Curettage: Physical removal of the bump using a small scraping tool (curette) after numbing cream is applied. Highly effective (85–95% clearance) in a single visit.
• Laser therapy: Pulsed dye laser or CO2 laser can destroy bumps in 2–3 sessions with minimal scarring.

For immunocompromised patients: Systemic treatments such as intravenous cidofovir may be used under specialist supervision when standard treatments fail.

What to Expect / Recovery

• In healthy individuals, untreated molluscum typically resolves within 6–18 months, though some cases last up to 2–3 years.
• With treatment, resolution is usually faster—often within 8–16 weeks depending on the method used.
• Multiple treatment sessions may be needed.
• Avoid scratching the bumps, as this spreads the virus to other skin areas and increases infection risk.
• In people with HIV or other immune conditions, molluscum can be much more difficult to treat and may require long-term antiviral therapy.

When to See a Dermatologist

Consider making an appointment if:

• You or your child has bumps that look like molluscum—especially if there are many of them or they are spreading.
• Bumps appear in sensitive areas (face, genitals, or near the eyes).
• The skin around the bumps is becoming red, swollen, or producing pus, which may indicate a bacterial infection.
• You are immunocompromised and develop molluscum-like bumps—prompt treatment is important.
• Over-the-counter treatments have not worked after several weeks.

Frequently Asked Questions

Q: Can molluscum contagiosum come back after it’s treated?
A: Re-infection is possible if you are exposed to the virus again, but the bumps that were treated do not typically recur at the same spots once fully cleared. Building up immunity through the infection may offer some protection against future infections.

Q: Should I keep my child home from school or daycare?
A: Molluscum is contagious through direct skin contact, so covering the bumps with clothing or a bandage significantly reduces transmission risk. Most schools do not require children to stay home, but checking with your child’s school policy is a good idea.

Q: Can adults get molluscum contagiosum?
A: Yes. In adults, molluscum is often sexually transmitted and appears in the genital area or inner thighs. Adults with healthy immune systems are 5–18 times more likely to get it if they are immunocompromised. Anyone can be infected at any age.

Q: Are there any long-term complications?
A: In healthy individuals, molluscum contagiosum does not cause long-term complications. Rarely, scratching may lead to scarring. In immunocompromised people, widespread, treatment-resistant infections can cause significant skin problems if left unmanaged.