Molluscum contagiosum

molluscum · molluscum contagiosum · water warts

Harmless, self-limiting and enormously common - the intervention is explanation, not treatment.

DISCHARGEBand B

Red flags

Very extensive or atypical lesions, or lesions on the face in an adult - consider immunosuppression including HIV
Genital lesions in a child - consider the possibility of sexual contact and follow safeguarding guidance, while recognising that autoinoculation from elsewhere is common and far more likely
Lesions near the eye with conjunctivitis
Genuine secondary bacterial infection with spreading cellulitis

Recognise

On light skin

Firm, dome-shaped, pearly pink papules 2 to 5 mm across with a central dimple, sometimes with surrounding eczema.

On brown and black skin

The pearly pink colour does not transfer; lesions in brown and black skin more often appear skin-coloured, brown or hyperpigmented, which can make them look like warts or other papules. The dome shape and the central umbilication are structural, not chromatic - look across the skin at an angle, in good light, to catch the dimple. Molluscum characteristically leaves conspicuous post-inflammatory hyperpigmentation at each site as lesions resolve, often for months, and parents should be warned that the marks outlast the lesions and do not mean the infection is persisting.

In any skin tone

Central umbilication - the dimple is the diagnosis
Firm, dome-shaped, usually 2 to 5 mm
In clusters, spread by direct contact and autoinoculation
Surrounding eczema is common and is often what brings them in
An inflamed, red, tender lesion usually means it is about to resolve, not that it is infected

Distribution

Clusters on the trunk, axillae, flexures and limbs, often where skin touches skin. Genital lesions in adults are usually sexually transmitted.

Photographs

Molluscum contagiosum on the face, neck and chest. Dome-shaped pearly papules of several different sizes, many with a dimple in the centre. — Molluscum contagiosum on the face, neck and chest. **Dome-shaped pearly papules of several different sizes, many with a dimple in the centre.** The pearly white surface stands out against dark skin, so this is one of the few conditions that is arguably easier to spot here than on pale skin. One cluster has become red and inflamed - that is usually the immune system clearing them, not bacterial infection.
Fitzpatrick IV-VI (Fitzpatrick type estimated from the photograph, not stated by the source) · Oladokun RE, Lehloenya RJ, Hlela C, Ubesie AC, Katibi SO, Malande OO, Eley BS · Atlas of Paediatric HIV Infection, UCT Libraries Press 2018 - Chapter 2: Viral Skin Infections, p48 · CC BY 4.0

Extensive molluscum with giant lesions, involving the eyelid, in an immunosuppressed child. Molluscum this numerous, this large, or this res — Extensive molluscum with **giant lesions, involving the eyelid**, in an immunosuppressed child. Molluscum this numerous, this large, or this resistant is a reason to think about underlying immunodeficiency rather than simply to reassure. Lid-margin lesions need ophthalmology.
Fitzpatrick IV-VI (Fitzpatrick type estimated from the photograph, not stated by the source) · Oladokun RE, Lehloenya RJ, Hlela C, Ubesie AC, Katibi SO, Malande OO, Eley BS · Atlas of Paediatric HIV Infection, UCT Libraries Press 2018 - Chapter 2: Viral Skin Infections, p49 · CC BY 4.0

Provenance for every photograph in this library: image licences. How much of the corpus still has no darker-skin photograph: skin tone coverage.

Mimics

Chickenpox (varicella) — Chickenpox lesions are vesicular, at mixed stages, and accompanied by fever
Atopic eczema and infected eczema — Molluscum eczema around lesions is common and both may need treating
Impetigo — An inflamed molluscum can be mistaken for impetigo and treated with antibiotics unnecessarily

What to do in the ED

Explain that it is harmless and self-limiting, but be honest about the timescale: CKS states that resolution usually occurs within 18 months, though lesions can persist for more than 3 or 4 years. Understating this is why families lose confidence and re-attend
Treatment is not routinely recommended - most interventions risk scarring and the condition resolves without them
Treat surrounding eczema, which is usually the actual complaint
No exclusion is required - molluscum does not appear in UKHSA's A to Z of infectious diseases in education and childcare settings at all, and where no exclusion period is set the guidance's position is that the person attends and interacts as usual. Swimming need not be restricted either, though that part is conventional advice rather than a UKHSA statement. Advise against sharing towels and against scratching
Warn that lesions often become red and inflamed shortly before they resolve, and that this is expected rather than infection
Consider immunosuppression in extensive or atypical disease; assess genital lesions in children within safeguarding guidance without assuming abuse

Disposition

DISCHARGE

Reassure and discharge. Refer only for extensive or atypical disease, suspected immunosuppression, or where a safeguarding concern arises.

Safety-netting

This clears by itself, usually within about 18 months, but in some children it takes considerably longer - occasionally more than three years. New spots appearing meanwhile is normal rather than a sign that anything is going wrong. Spots often go red and angry just before they disappear. Return if a spot becomes very painful with spreading redness around it, if spots appear near the eye and the eye becomes red, or if they become very widespread. Darker marks left where spots have been will fade slowly and are not scars.

Sources

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