Small Shiny Bumps That Spread (Molluscum Contagiosum), Explained

If a child in your house has suddenly grown a scattering of small, smooth, pearly bumps — often in a cluster, often in a skin fold, each one with a tiny dimple in the middle — the most likely answer is molluscum contagiosum. It looks alarming for something so benign, it spreads while you watch, and it takes far longer to go away than feels reasonable.

The good news arrives early and stays: in a healthy immune system this clears completely, on its own, without leaving a mark. The frustrating news is the timeline.

What it looks like

The classic lesion is a flesh-coloured or pink dome-shaped papule, 2 to 5 mm across, with a small central dimple — the medical word is umbilication, and it's the single most useful identifying feature. The surface is smooth and slightly shiny rather than rough.

Children usually have somewhere between 10 and 20 of them, though the number can be far higher (StatPearls). They cluster where skin touches skin or where a child scratches: armpits, the backs of the knees, the trunk, the neck, the face. They're typically painless, but they can itch — and the itching is what makes them spread.

If you're trying to place a bump that doesn't fit this description, white bumps on your skin, decoded runs through the look-alikes — milia, whiteheads, sebaceous hyperplasia and the rest.

What causes it

Molluscum contagiosum virus, a double-stranded DNA virus in the poxvirus family. Four genotypes exist; MCV-1 accounts for roughly 90% of cases in the US.

It is worth being clear that this is not the same as warts, which are caused by human papillomavirus, and not a bacterial infection like impetigo. The distinction matters mainly because the treatments and the natural history are different.

Who gets it: most commonly children aged 1 to 14, with a median around 5. It also turns up in sexually active adolescents and adults, and — importantly — in people whose immune systems are suppressed.

How it spreads

Four routes, in rough order of how often they matter:

1. Direct skin-to-skin contact with someone who has active bumps.
2. Autoinoculation — the person spreading it to themselves. Scratching a lesion and then touching elsewhere moves the virus to new skin. This is why a tidy cluster becomes a scattered one.
3. Shared objects — towels, clothing, sports equipment, bath water. DermNet notes that transmission "appears to be more likely in wet conditions, such as when children bathe or swim together."
4. Sexual contact in adults, which is why genital lesions in an adult are a different conversation (see below).

The practical prevention list is short: cover visible bumps with clothing or a watertight bandage, don't share towels or personal items, and — hardest of all with a child — try to interrupt the scratching.

Why children with eczema get it worse

This is the connection worth knowing if it applies to you. Children with atopic dermatitis are at particularly high risk, because a disrupted barrier plus frequent scratching gives the virus both an entry point and a delivery mechanism.

The numbers back it up. In a review of 170 children evaluated for molluscum at a US paediatric centre, 46.5% had a history of atopic dermatitis, and those children had significantly more lesions than those without (Basdag, Rainer & Cohen, Pediatric Dermatology 2015).

So if eczema is in the picture, controlling the eczema is part of controlling the molluscum — not a separate project. How to treat and manage eczema, what causes eczema flare-ups and, for the youngest, baby eczema.

Molluscum dermatitis: the red itchy ring

At some point many of the bumps develop a patch of pink, dry, itchy skin around them. This is alarming to look at and frequently mistaken for infection.

It usually isn't. It's an inflammatory immune response to the virus — and it often signals that the body is starting to clear the infection. DermNet notes that this secondary dermatitis "is unlikely to fully resolve until the molluscum infection has cleared up," so it can be soothed but not really cured ahead of the molluscum itself. Gentle moisturising helps; so does anything that reduces scratching, since the dermatitis itself drives more spread.

How long it actually takes

Here is the honest number, and it's the reason this article exists.

About 50% of lesions clear within 12 months and around 70% within 18 months, without treatment (StatPearls). DermNet gives essentially the same figures: about half cleared by 12 months and two-thirds by 18, with or without treatment. The AAD's public guidance says bumps clear in 6 to 18 months on average. A minority run 2 to 5 years.

Individual bumps come and go faster than that — a given lesion lasts weeks to a couple of months — but new ones keep appearing from autoinoculation, which is why the whole episode drags.

To treat, or to wait?

The instinct is to treat. The evidence makes that a genuinely open question.

In the 170-child review above, 72.9% received no treatment at all. Lesions cleared within 12 months in 45.6% of treated versus 48.4% of untreated children, and within 18 months in 69.5% versus 72.6%. The authors' conclusion is worth quoting plainly: treatment did not shorten the time to resolution. Nor did sex, race, lesion count, location or eczema history predict how long it would take.

That is one retrospective study at one centre, not the last word, and a 2019 review (Meza-Romero, Navarrete-Dechent & Downey) describes the treat-or-not question as still debated — with consensus favouring intervention for extensive disease, complications, or genuine distress about appearance.

So the reasonable position is: waiting is a legitimate plan, not neglect, and treating is reasonable when there's a specific reason to.

When the AAD suggests treating

• There's a chronic skin condition like eczema in the mix
• The lesions are genital
• The immune system is weakened and the bumps are numerous
• They're simply bothering the person enough to matter

What treatment looks like

In a clinic: cantharidin (a blistering agent, FDA-approved from age 2, which raises a blister over 24–48 hours), cryosurgery with liquid nitrogen, curettage — scraping the lesions, better tolerated by older children and adults — and pulsed dye laser for numerous bumps, which is effective but expensive and rarely covered. Prescription at-home options include berdazimer gel, imiquimod cream, salicylic acid and tretinoin.

What not to do

The AAD is unusually direct here, on two points.

On removing them yourself with forceps or a blade: "You should not try this at home. Without proper technique, you can cause a serious infection."

On products bought online: "If you buy this treatment online and apply it at home, you risk serious side effects, such as deep chemical burns, intense pain, and permanent scarring." The FDA's position is that non-prescription products marketed for molluscum are unlikely to do what they claim.

Untreated molluscum clears without a scar. Aggressive home removal is one of the few ways to end up with one.

When to see a doctor

Most molluscum needs patience and a clinician's confirmation, not urgency. These are the exceptions:

• Genital bumps in an adult. These indicate sexual transmission and warrant a proper conversation about testing and partners — not something to manage from an article.
• A weakened immune system. In immunocompromised people, and in HIV specifically, lesions become larger (over 10–15 mm), far more numerous, widely spread and resistant to standard treatment. StatPearls puts prevalence in people with HIV at around 20%. This needs medical management.
• Signs of bacterial infection — increasing pain, spreading redness, warmth, pus, or fever. The AAD notes that scratching can introduce bacteria and cause pain and fever. See impetigo and cellulitis.
• Bumps on the eyelid or very close to the eye, which can irritate the eye itself and shouldn't be treated at home.
• A bump that doesn't fit the pattern — one that grows steadily, bleeds, ulcerates, or won't heal. Molluscum is not the only thing that looks like a small bump, and non-healing is always the overriding rule. Skin cancer warning signs and moles: when to worry.
• Any molluscum in a child you haven't had confirmed. A diagnosis is usually made on sight in a single visit, and it's worth having, because the plan afterwards is mostly reassurance.

The short version

Molluscum contagiosum is a common poxvirus infection that produces small, smooth, dimpled bumps, mainly in children, and mainly on skin that touches skin. It spreads by scratching more than by anything else, hits children with eczema hardest, and reliably clears on its own — about half within a year, most within 18 months. Treatment exists and is worth it for genital lesions, extensive disease, a weakened immune system or real distress, but the best available evidence suggests it doesn't make the whole episode end sooner. Cover the bumps, don't share towels, keep school and swimming going, and don't dig them out at home.

For a child, the first stop is your paediatrician or a dermatologist — a diagnosis on sight takes one appointment and settles most of the anxiety. For an adult trying to work out whether the bumps you're looking at fit this pattern at all, a skin assessment can help you describe what you're seeing before that appointment. It's informational, not a diagnosis, and it doesn't replace being examined — genital lesions, a weakened immune system, or anything infected or non-healing should go straight to a clinician.