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Molluscum contagiosum
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Exam Tips
- Classic OSCE diagnosis is clinical: multiple 2-5 mm pearly, umbilicated papules in a child with otherwise well appearance.
- In adults, genital molluscum should prompt STI risk assessment and offer of sexual health screening.
- Think immunosuppression if lesions are facial, giant, atypical, or very numerous (>100).
- Peri-ocular lesions plus red eye require urgent ophthalmology review.
- See Figure: typical umbilicated papules in your dermatology teaching atlas for visual pattern recognition.
Definition
Molluscum contagiosum is a common, benign cutaneous infection caused by molluscum contagiosum virus (a poxvirus), producing characteristic dome-shaped papules with central umbilication. In UK practice it is usually diagnosed clinically, most often in children through close skin contact, while genital disease in adults is more often sexually acquired. The condition is typically self-limiting but can be more extensive, persistent, or atypical in people who are immunocompromised.
Pathophysiology
MCV infects epidermal keratinocytes and replicates in the cytoplasm, driving epidermal hyperplasia and formation of pearly papules with a central keratin plug (umbilication). Spread occurs by direct skin contact, autoinoculation (scratch spread/Koebnerization), and fomites; vertical transmission is reported. MCV-1 causes most paediatric disease, while MCV-2 is relatively more common in sexually transmitted and HIV-associated presentations. Unlike herpes viruses, MCV does not establish latent infection, so later disease in immunosuppression reflects new/persistent infection rather than reactivation.
Risk Factors
- Close skin-to-skin contact (including household and sexual contact) and autoinoculation
- Shared fomites (for example towels/flannels), and possible association with swimming
- Atopic dermatitis (impaired skin barrier and immune dysregulation)
- Immunosuppression: HIV, transplant status, systemic immunosuppressive therapy, neoplasia, sarcoidosis, SLE
- Warm/humid climates
Clinical Features
Symptoms
- Often asymptomatic
- Mild itch or irritation
- Cosmetic distress/embarrassment
- Redness or eczematous flare around lesions (molluscum dermatitis)
- Tenderness/discharge if secondarily infected
Signs
- Firm, smooth, flesh-coloured to pearly dome-shaped papules with central umbilication
- Usually 2-5 mm; may be solitary or clustered (commonly 1-30 lesions)
- Children: trunk and flexures common; anogenital lesions can occur
- Adults with sexual transmission: genitalia, pubis, thighs, lower abdomen
- Atypical/extensive disease (including facial, giant >=1 cm, cystic/ulcerated lesions) suggests immunocompromise
- Eyelid-margin lesions may be associated with conjunctivitis/red eye
Investigations
Clinical diagnosis:Typical umbilicated papules usually sufficient; routine laboratory tests not required
STI screen in adults with anogenital lesions:Assess for co-existing sexually transmitted infections per GUM pathway
HIV testing (especially severe/extensive/atypical or recalcitrant disease):May identify underlying immunosuppression when lesions are numerous, giant, facial, or persistent
Specialist assessment when uncertain:Dermatology review (and occasionally biopsy) if diagnosis unclear or lesion morphology atypical
Management
Lifestyle Modifications
- Reassure: usually self-resolving; avoid routine exclusion from school/nursery/swimming
- Reduce spread/autoinoculation: avoid scratching, avoid sharing towels/flannels, cover visible lesions for contact sports
- Do not squeeze or pick lesions (increases inflammation, bacterial infection risk, and scarring)
- Safety-net for red flags: rapid spread, marked pain, purulence, eye involvement, or immunosuppression
- Use emollients to maintain skin barrier, especially if coexistent atopic eczema
Pharmacological Treatment
Topical corticosteroid for molluscum dermatitis (surrounding eczema, not antiviral treatment)
- Hydrocortisone 1% cream or ointment: apply thinly once or twice daily to inflamed eczematous skin for up to 7 days
Use the lowest potency for the shortest duration; avoid prolonged use on face/genitals and avoid direct ocular contact. This treats associated eczema/itch, not viral clearance.
Antibacterial treatment only if secondary bacterial infection is present
- Flucloxacillin 500 mg orally four times daily for 5-7 days (adult dosing per BNF skin/soft-tissue infection guidance)
Not indicated for uncomplicated molluscum. Check penicillin allergy and local antimicrobial guidance; consider alternatives (for example macrolide) if true penicillin hypersensitivity.
Surgical / Interventional
- Usually not required in primary care because spontaneous resolution is expected
- If treatment is needed (for persistent, troublesome, or genital lesions): clinician-delivered curettage, cryotherapy, or cautery
- Warn about procedure pain, post-inflammatory change, and scarring risk; avoid destructive self-treatment near eyes/genitals
- Urgent ophthalmology referral for eyelid-margin lesions with red eye; urgent HIV specialist input for extensive lesions in known HIV
Complications
- Pruritus and erythema (common inflammatory reaction)
- Molluscum dermatitis (eczematous halo) and delayed clearance, especially with atopic dermatitis
- Secondary bacterial infection from excoriation
- Scarring (usually mild and often not permanent)
- Psychological distress related to visible lesions
- Ocular complications (follicular conjunctivitis, rarely corneal involvement) with peri-ocular disease
- Rare hypersensitivity eruptions (for example erythema multiforme-like reactions)
Prognosis
Excellent in immunocompetent patients: lesions generally clear spontaneously, commonly within about 18 months, though persistence for 3-4 years can occur. Disease may be longer-lasting and far more extensive in immunocompromised patients (including HIV), where individual lesions can persist for years and specialist management is often needed.
Sources & References
🏥BMJ Best Practice(1)
✅NICE Guidelines(1)
- Molluscum contagiosum[overview]
📖Textbook References(20)
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1588)[context]
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1588)[context]
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1094)[context]
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1581)[context]
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1658)[context]
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1650)[context]
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1587, 1588)[context]
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1093, 1094)[context]
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1587, 1588)[context]
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1492, 1493)[context]
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1651, 1652)[context]
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1649, 1650)[context]
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1581)[context]
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1657, 1658)[context]
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1581)[context]
- David Randall PhD MRCP (Editor), John Booth PhD MRCP (Editor), K - Kumar and Clark's Clinical Medicine (2025, American Elsevier Publishing Co.) - libgen.li.pdf(pp. 1652, 1653)[context]
- Oxford Handbook of Clinical Diagnosis (Huw Llewelyn, Hock Aun Ang, Keir Lewis etc.) (Z-Library).pdf(pp. 672)[context]
- Oxford Handbook of Clinical Diagnosis (Huw Llewelyn, Hock Aun Ang, Keir Lewis etc.) (Z-Library).pdf(pp. 671, 672)[context]
- Oxford Handbook of Clinical Diagnosis (Huw Llewelyn, Hock Aun Ang, Keir Lewis etc.) (Z-Library).pdf(pp. 146, 147)[context]
- [Williams, Bailey and Love's Short Practice of Surgery] Norman Williams, Christopher Bulstrode, P Ronan O'Connell - Bailey & Love's Short Practice of Surgery 26E (2013, CRC Press) - libgen.li.pdf(pp. 641)[context]