Molluscum Contagiosum: Symptoms, Causes & Treatment

What Is Molluscum Contagiosum?

Molluscum contagiosum is a common, harmless viral skin infection caused by the molluscum contagiosum virus (MCV), a type of poxvirus. It produces small, flesh-colored, dome-shaped bumps on the skin that have a characteristic dimple in the center. The condition affects approximately 2-8% of children worldwide and typically resolves without treatment.

Molluscum contagiosum, sometimes called "water warts" or simply "molluscum," is one of the most common viral skin infections in children. The condition gets its name from the Latin word "molluscus," meaning soft, referring to the soft, rounded appearance of the bumps. Despite being called "contagious," the infection is generally mild and poses no serious health risks.

The virus that causes molluscum contagiosum belongs to the poxvirus family, which includes other viruses like smallpox and cowpox. However, unlike these relatives, molluscum contagiosum virus only causes a localized skin infection and cannot spread to internal organs or cause systemic illness. The virus infects only the outer layer of skin (epidermis) and triggers the characteristic bump formation.

While molluscum contagiosum is most commonly seen in children between the ages of 2 and 5 years, it can affect people of any age. Adults can also develop the infection, though this is less common. In healthy individuals with normal immune systems, molluscum contagiosum is a self-limiting condition, meaning it will eventually clear up on its own without any treatment. This natural resolution occurs because the immune system eventually recognizes and eliminates the virus.

Who Gets Molluscum Contagiosum?

Certain groups are more likely to develop molluscum contagiosum than others. Understanding these risk factors can help in recognizing and preventing the spread of the infection. Children aged 2-5 years have the highest incidence of molluscum contagiosum, likely due to close contact with other children in daycare or school settings combined with less developed immune responses.

Individuals with atopic dermatitis (eczema) are particularly susceptible to molluscum contagiosum. The compromised skin barrier in eczema makes it easier for the virus to establish infection, and affected individuals often develop more numerous lesions. The virus tends to spread more readily in eczematous skin, which is why treating any underlying eczema is an important part of managing molluscum contagiosum.

People with weakened immune systems, including those with HIV/AIDS, organ transplant recipients on immunosuppressive medications, or individuals receiving chemotherapy, may develop more extensive and persistent molluscum contagiosum infections. In these cases, the bumps may be larger, more numerous, and take longer to resolve.

How Common Is Molluscum Contagiosum?

Molluscum contagiosum is a very common condition worldwide, though precise prevalence figures vary depending on the population studied and geographic region. Studies estimate that between 2% and 8% of children are affected at any given time, making it one of the most frequently encountered viral skin conditions in pediatric practice.

The prevalence is higher in tropical and subtropical climates, where warm, humid conditions may facilitate virus transmission. Outbreaks can occur in settings where children have close physical contact, such as daycare centers, schools, and swimming pools. However, the infection is not limited to any particular socioeconomic group or geographic area.

What Are the Symptoms of Molluscum Contagiosum?

Molluscum contagiosum causes small, round, dome-shaped bumps (papules) that are 2-5 mm in diameter with a characteristic central dimple (umbilication). The bumps have a smooth, waxy, or pearly appearance and are usually flesh-colored or slightly pink. Children commonly develop them on the stomach, arms, face, and neck, ranging from a few bumps to many.

The hallmark of molluscum contagiosum is the distinctive appearance of the skin bumps. Unlike many other skin conditions, molluscum has several characteristic features that make it relatively easy to identify. Each individual bump, called a papule or lesion, has a smooth, dome-shaped surface that looks almost waxy or pearly when examined closely. The bumps are typically firm to the touch but not hard like warts.

The most distinctive feature of molluscum contagiosum is the small dimple or depression in the center of each bump, known medically as "umbilication." This central indentation is caused by the way the virus affects skin cells and is often visible to the naked eye, though it may be more apparent when the skin is stretched or examined with magnification. The umbilication contains a white, cheesy material made up of dead skin cells and viral particles.

The color of molluscum bumps can vary depending on an individual's skin tone. On lighter skin, the bumps typically appear flesh-colored, slightly pink, or pearly white. On darker skin tones, the bumps may appear lighter than the surrounding skin, or they may have a slightly different hue. This variation in color is important to recognize to avoid misdiagnosis in people with different skin types.

Common Locations for Molluscum Bumps

In children, molluscum contagiosum bumps most commonly appear on the following areas:

• Trunk (stomach and chest): The most common location for molluscum in children
• Arms and legs: Particularly in areas of skin folds or where clothing rubs
• Face: Including around the eyelids, though care must be taken if bumps appear near the eyes
• Neck: Often in conjunction with facial lesions
• Armpits: Where warm, moist conditions may facilitate spread

The number of bumps can vary significantly from person to person. Some individuals may have only a few isolated lesions, while others can develop dozens or even hundreds of bumps. Children with eczema tend to develop more numerous lesions because the compromised skin barrier makes them more susceptible to both initial infection and autoinoculation (self-spreading).

Signs That Bumps Are Resolving

Before molluscum bumps disappear, they often go through a characteristic change in appearance that indicates the immune system is successfully fighting the infection. This process, sometimes called the "beginning of the end," typically involves the bumps becoming inflamed, red, and swollen. While this can look concerning to parents, it's actually a positive sign.

During this inflammatory phase, the bumps may become itchy or slightly tender. They may also develop a crusty surface as they begin to break down. This inflammation is caused by the immune system finally recognizing and attacking the virus. Within a few weeks of this inflammatory phase, the bumps typically flatten and disappear, usually without leaving any permanent marks.

Complications and Associated Symptoms

While molluscum contagiosum itself is harmless, several associated conditions can develop that may require attention:

Molluscum dermatitis: A patch of eczema-like rash that develops around molluscum bumps, affecting up to 10-15% of people with molluscum. This itchy, red rash is caused by the immune system's response to the virus and can be treated with mild steroid creams.

Secondary bacterial infection: If bumps become scratched or picked at, bacteria can enter the skin and cause infection. Signs include increased redness spreading beyond the bump, warmth, pus, and increasing pain. This may require treatment with topical or oral antibiotics.

Eye involvement: When molluscum bumps develop on or near the eyelids, they can sometimes cause irritation of the eye itself (conjunctivitis) or other eye problems. Bumps near the eyes should be evaluated by a healthcare provider.

What Causes Molluscum Contagiosum?

Molluscum contagiosum is caused by the molluscum contagiosum virus (MCV), a DNA virus belonging to the poxvirus family. The virus spreads through direct skin-to-skin contact, contact with contaminated objects like towels or toys, and can spread to other parts of the body through scratching. Once infected, symptoms typically appear 2-7 weeks later.

The molluscum contagiosum virus (MCV) is a large, brick-shaped DNA virus that exclusively infects humans. Unlike many other viruses, MCV cannot be grown in standard laboratory cell cultures, which has historically limited research into the condition. There are four subtypes of the virus (MCV-1 through MCV-4), with MCV-1 being the most common cause of infection in children.

When the virus comes into contact with the skin, it enters the cells of the epidermis (the outer layer of skin) and begins to replicate. The infected cells multiply and form the characteristic dome-shaped bump. Inside each bump is a core of infected cells containing large quantities of viral particles. This is why the bumps are contagious - they contain the active virus that can spread to others or to other areas of the same person's body.

The incubation period - the time between exposure to the virus and the appearance of symptoms - typically ranges from 2 to 7 weeks, though it can sometimes be longer. This relatively long incubation period means that by the time bumps appear, the original source of infection may be difficult to identify.

How Does Molluscum Spread?

Understanding how molluscum contagiosum spreads is important for both preventing new infections and limiting the spread to others. The virus can be transmitted through several mechanisms:

Direct skin-to-skin contact: This is the most common route of transmission. The virus passes from an infected area of skin to uninfected skin through physical contact. In children, this commonly occurs during play, while in adults, sexual contact is a frequent mode of transmission.

Fomite transmission: The virus can survive on objects and surfaces for a period of time, allowing transmission through shared items. Common fomites include towels, washcloths, clothing, toys, and sports equipment. Swimming pools and shared bathing facilities have been suggested as potential sources of transmission, though the exact role of water in spreading the virus is debated.

Autoinoculation: This refers to the spread of virus from one area of the body to another through scratching, picking, or shaving. This is why molluscum bumps often appear in clusters or lines - they spread along the path of scratching. Autoinoculation is particularly common in children who scratch itchy bumps and in individuals with eczema.

Risk Factors for Infection

Several factors can increase the likelihood of acquiring molluscum contagiosum or experiencing a more extensive infection:

• Age: Children aged 2-5 years are most commonly affected
• Atopic dermatitis (eczema): Compromised skin barrier increases susceptibility
• Warm, humid climates: Higher prevalence in tropical regions
• Close contact settings: Daycare, schools, swimming pools
• Immunosuppression: HIV, organ transplantation, chemotherapy
• Contact sports: Wrestling, gymnastics, and other close-contact activities

How Is Molluscum Contagiosum Treated?

The recommended approach for most cases of molluscum contagiosum is watchful waiting, allowing the bumps to resolve naturally over 6-12 months. Treatment is generally not necessary and may cause more harm than benefit. If treatment is desired, options include topical treatments, cryotherapy (freezing), and curettage, but these can be painful and may cause scarring.

The management of molluscum contagiosum has evolved significantly in recent years, with growing recognition that active treatment is often unnecessary and potentially counterproductive. Most dermatology guidelines now recommend watchful waiting as the first-line approach for immunocompetent children with uncomplicated molluscum. This recommendation is based on several important factors.

First, molluscum contagiosum is a self-limiting condition that will eventually resolve without any intervention. The immune system is capable of recognizing and eliminating the virus, though this process takes time. Second, many treatment methods are painful, particularly for children, and can create negative associations with medical care. Third, treatments themselves can cause scarring, whereas naturally resolving lesions rarely leave permanent marks.

The decision to treat should be made on an individual basis, considering factors such as the location and number of lesions, the patient's (or parent's) preferences, any complications such as secondary infection or significant itch, and whether the lesions are causing psychosocial distress. In general, treatment may be more strongly considered when lesions are in cosmetically sensitive areas, when there are complications, or when the patient is immunocompromised.

Self-Care and Home Management

For most people with molluscum contagiosum, home management focuses on preventing spread and managing any associated symptoms rather than treating the bumps themselves. Here are key self-care strategies:

Avoid scratching and picking: This is perhaps the most important advice. Scratching or picking at molluscum bumps can lead to spread of the virus to other areas, secondary bacterial infection, and scarring. Keep fingernails trimmed short and clean to minimize damage if scratching does occur.

Treat associated eczema: If eczema (molluscum dermatitis) develops around the bumps, it should be treated to reduce itching and prevent scratch-induced spread. Mild hydrocortisone cream (available over-the-counter) can be used on the eczematous areas around the bumps, though not on the bumps themselves. For more severe eczema, consult a healthcare provider.

Keep skin moisturized: Regular use of fragrance-free moisturizers helps maintain skin barrier function and may reduce itching. This is particularly important for individuals with underlying eczema.

Cover lesions when appropriate: Covering bumps with clothing or waterproof bandages can reduce transmission during activities involving close contact. However, this is not necessary for everyday activities at school or daycare.

Over-the-Counter Products

A topical product containing potassium hydroxide is available in some countries as an over-the-counter treatment for molluscum contagiosum. This solution is applied directly to the bumps twice daily and may help speed resolution of the lesions. The product works by causing controlled irritation of the bumps, which triggers an immune response.

This treatment can be used in children from age 2 years, but it may cause skin irritation in some individuals. If significant irritation occurs, the treatment should be stopped. Parents should consult a pharmacist or healthcare provider for advice on proper use.

Medical Treatment Options

When treatment is deemed necessary, several medical options are available. However, it's important to understand that no treatment has been proven in high-quality studies to be significantly better than watchful waiting, and all treatments carry some risk of side effects:

Cryotherapy: Freezing with liquid nitrogen is one of the most commonly used treatments. It works by destroying the infected cells through cold injury. Cryotherapy can be painful and often requires multiple sessions. It may cause temporary blistering and can leave white marks or scars, particularly on darker skin.

Curettage: Physical removal of bumps using a small, spoon-shaped instrument called a curette. This is usually done under local anesthesia to minimize pain. Curettage is effective but can cause bleeding and may leave small scars. It's typically reserved for larger or more bothersome lesions.

Topical treatments: Various prescription topical treatments may be used, including tretinoin, imiquimod, and cantharidin (where available). These work through different mechanisms but generally require multiple applications and can cause skin irritation.

When Should You See a Doctor?

Most people with molluscum contagiosum don't need to see a doctor, as the condition typically resolves on its own. However, you should seek medical advice if bumps appear near the eyes, if there are signs of bacterial infection (increasing redness, warmth, pus), if you or your child has a weakened immune system, or if the bumps are causing significant distress.

While molluscum contagiosum is generally a harmless condition that doesn't require medical attention, there are certain situations where consulting a healthcare provider is advisable. Understanding when to seek care helps ensure that any complications are addressed promptly while avoiding unnecessary medical visits for uncomplicated cases.

Signs of bacterial infection: If a molluscum bump becomes increasingly red, warm, swollen, or painful, or if pus is visible, this may indicate a secondary bacterial infection. This requires medical evaluation and may need treatment with topical or oral antibiotics. Signs that spreading cellulitis may be developing include redness extending beyond the immediate area of the bump and fever.

Eye involvement: Molluscum bumps on or near the eyelids warrant medical attention. While the bumps themselves are benign, their location near the eye can sometimes lead to irritation of the eye itself, including conjunctivitis. An ophthalmologist may need to be involved if eye symptoms develop.

Immunocompromised individuals: People with weakened immune systems, including those with HIV, organ transplant recipients, or individuals receiving immunosuppressive therapy, should have molluscum contagiosum evaluated by a healthcare provider. The infection may be more extensive and persistent in these individuals and may require different management approaches.

Diagnostic uncertainty: If there is any doubt about the diagnosis, medical evaluation can confirm that the bumps are indeed molluscum and not another condition. This may be particularly important in adults where lesions in the genital area need to be distinguished from other sexually transmitted infections.

Significant psychosocial impact: If molluscum is causing significant distress to a child or affecting their quality of life (for example, if they're being teased at school or refusing to participate in activities), discussing treatment options with a healthcare provider may be worthwhile.

How Can You Prevent Spreading Molluscum Contagiosum?

To prevent spreading molluscum, avoid sharing towels, washcloths, and clothing with others. Don't scratch or pick at the bumps. Cover lesions with clothing when possible during close contact. However, children with molluscum can attend school, daycare, and swimming activities normally - the infection is not dangerous and extreme isolation measures are not recommended.

While complete prevention of molluscum contagiosum transmission is difficult, particularly in children who have close contact with others, several measures can help reduce spread. It's important to maintain perspective: molluscum is a harmless infection, and the goal of prevention is to minimize spread without imposing excessive restrictions that might negatively impact a child's social development and activities.

Personal hygiene items: The most effective prevention measure is to avoid sharing personal items that come into contact with the skin. Each family member should have their own towels, washcloths, and similar items. This is good practice in general and helps prevent transmission of many different infections, not just molluscum.

Avoid touching bumps: Try to avoid touching molluscum bumps, and wash hands thoroughly if contact does occur. Teaching children not to scratch or pick at their bumps is important both for preventing spread to others and for avoiding autoinoculation (spreading the virus to other areas of their own body).

Covering lesions: When practical, covering molluscum bumps with clothing or waterproof bandages can reduce transmission during activities involving close physical contact. However, covering is not necessary for everyday activities and may not be practical for lesions on the face or other exposed areas.

Activities and Social Participation

A common concern among parents is whether children with molluscum contagiosum can participate in normal activities. The good news is that children with molluscum can and should continue their usual activities, including:

• School and daycare: There is no need to exclude children with molluscum from school or childcare settings
• Swimming: Children can participate in swimming activities, though covering visible lesions with waterproof bandages may be considerate
• Sports: Most sports activities can continue, though covering exposed lesions during contact sports may be advisable
• Social activities: Normal play dates and social interactions should continue

The rationale for allowing continued participation in activities is that molluscum is extremely common, generally harmless, and the benefits of normal social development outweigh the minor risks of transmission. Excluding children from activities can cause psychological harm and is not necessary from a public health standpoint.

Molluscum Contagiosum in Adults

In adults, molluscum contagiosum is often transmitted through sexual contact, with bumps typically appearing on the lower abdomen, groin, genitals, and upper thighs. Despite this mode of transmission, molluscum is not classified as a sexually transmitted infection (STI) and does not require reporting to health authorities. The condition clears on its own and does not cause long-term problems.

While molluscum contagiosum is predominantly a childhood condition, it can also affect adults. The presentation and transmission patterns in adults differ somewhat from those seen in children, and understanding these differences is important for appropriate management and counseling.

In adults, molluscum contagiosum is most commonly acquired through sexual contact with an infected partner. The virus is transmitted through skin-to-skin contact during intimate activities, which explains why lesions in adults typically appear in the genital and surrounding areas. Common locations include the lower abdomen, pubic area, inner thighs, external genitalia, and groin.

It's important to note that molluscum contagiosum is not considered a sexually transmitted infection in the traditional sense. Unlike conditions such as chlamydia, gonorrhea, or HIV, molluscum does not cause systemic infection or long-term health consequences. It is not a reportable condition, meaning there is no requirement to notify health authorities or past partners. The infection will resolve on its own, and partners will develop immunity once their infection clears.

Adults with genital molluscum may wish to discuss the condition with their sexual partners and may choose to abstain from sexual activity or use barriers during the active infection to reduce transmission risk. However, these are personal decisions rather than public health requirements.

Non-Sexual Transmission in Adults

While sexual transmission is the most common route in adults, molluscum contagiosum can also be acquired through non-sexual contact. Adults who work closely with children (such as childcare workers and teachers) may acquire the infection through occupational exposure. Similarly, athletes involved in contact sports may transmit the virus through skin-to-skin contact during competition or training.

Shaving can also contribute to the spread of molluscum in adults. The razor can transfer viral particles from one area to another, leading to linear distributions of lesions along shaving lines. This is most commonly seen in areas of regular shaving such as the beard area in men or the legs in women.