Molluscum contagiosum in genital sites

01OverviewDefinition, clinical context and the essential points that orientate the chapter.

Molluscum contagiosum virus is a poxvirus confined to epidermis. It creates firm umbilicated papules containing a white keratinous core. In adults, lesions limited to pubic, genital, perineal or adjacent lower-abdominal skin are often acquired through close sexual skin contact, but the diagnosis cannot identify a particular partner or precisely date transmission. Autoinoculation through scratching or shaving can create linear crops.

An immunocompetent person commonly clears lesions through cell-mediated immunity over months. Treatment can shorten visible disease for preference, symptoms, transmission concern or lesion location, but each destructive or topical method can cause pain, ulceration, pigment change or scarring. Shared decision-making should compare these harms with observation. Imiquimod is specifically not recommended in the current BASHH genital guideline.

Extensive, giant or facial disease is uncommon in an otherwise well adult and should prompt HIV testing and a broader immune review. In people living with advanced HIV, effective antiretroviral treatment restores immune control and is central to improvement. Individual lesions may still be treated, but local therapy alone cannot substitute for diagnosing and treating immune deficiency.

Key points

Genital molluscum produces discrete, smooth, firm pearly or flesh-coloured papules with a central umbilication.
Diagnosis is usually clinical; dermoscopy or biopsy is reserved for atypical, giant, ulcerated, pigmented or uncertain lesions.
Offer routine STI screening to adults with genital disease and offer HIV testing when lesions are extensive, facial, giant or refractory.
Expectant management is recommended for most immunocompetent adults because lesions usually resolve spontaneously without scarring.
When active treatment is preferred, BASHH supports clinician cryotherapy or carefully instructed podophyllotoxin for suitable external lesions; evidence is limited.
Imiquimod is not recommended for genital molluscum because benefit was not shown and application reactions occur.
Use emollient and a mild topical corticosteroid for associated dermatitis rather than treating every inflamed lesion as bacterial infection.
Cryotherapy and cautery can be used in pregnancy, while podophyllotoxin should be avoided; treatment site and patient preference remain important.

02AetiologyUnderlying causes, associations and risk factors, with why each one matters.

Direct skin contact

Virus transfers from an infected epidermal lesion to susceptible skin during close contact, including genital sexual contact.

Autoinoculation

Scratching, squeezing, shaving or hair removal carries viral cores to adjacent disrupted epidermis and creates new crops.

Fomite exposure

Shared towels, razors or equipment can transfer virus, although genital adult disease is often linked to close contact.

Immune suppression

Impaired cellular immunity permits high viral burden, prolonged lesions and giant or atypically distributed disease. This distinction guides safe assessment and avoids unsupported changes to diagnosis, prophylaxis or treatment.

03PathophysiologyThe causal sequence from the underlying abnormality to symptoms and harm.

1
Epidermal entry
Poxvirus enters through microscopic barrier disruption and infects basal keratinocytes without systemic viraemia. This distinction guides safe assessment and avoids unsupported changes to diagnosis, prophylaxis or treatment.
2
Intracytoplasmic replication
Viral replication produces large inclusion bodies that displace the nucleus and fill the central keratinous core.
3
Immune evasion
Viral proteins suppress local inflammatory signalling, allowing pearly lesions to persist despite visible viral burden. This distinction guides safe assessment and avoids unsupported changes to diagnosis, prophylaxis or treatment.
4
Cell-mediated clearance
Delayed T-cell recognition produces inflammation and eventual destruction, often leaving normal skin without scarring. This distinction guides safe assessment and avoids unsupported changes to diagnosis, prophylaxis or treatment.

04Clinical features and red flagsSymptoms, examination findings, patterns of presentation and time-critical warnings.

Classic molluscum papule

A small smooth dome-shaped firm papule with central dell and pearly or flesh-coloured surface is characteristic.

Autoinoculated crop

Linear groups after scratching or shaving indicate local self-spread across microtraumatised skin.

Molluscum dermatitis

Eczematous redness and itch can surround lesions during infection or immune-mediated resolution.

Inflamed resolving lesion

A red tender-looking papule can reflect immune clearance, but spreading erythema or pus suggests bacterial infection.

Advanced immune phenotypeRed flag

Large, confluent, numerous or facial lesions in an adult point to impaired cellular immunity.

Atypical solitary lesionRed flag

Pigmentation, ulceration, bleeding or induration requires biopsy consideration for tumour or another infection.

Red flags requiring action

Numerous giant, confluent or facial lesions in an adult warrant assessment for advanced HIV or another cause of immune suppression.
A pigmented, ulcerated, indurated, painful or bleeding lesion is atypical and requires reconsideration or biopsy rather than presumptive treatment.
Spreading erythema, purulent discharge, fever or severe tenderness suggests secondary bacterial infection rather than uncomplicated molluscum inflammation.
Periocular lesions or lesions immediately adjacent to a mucosal opening need specialist treatment to avoid ocular or structural injury.
Genital lesions in a child require a careful paediatric and safeguarding assessment without assuming a sexual route from the diagnosis alone.

05InvestigationsWhat to request, why it matters and how to interpret it.

Investigation order

Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.

01
Whole-site clinical examinationFirst step
Why
Confirm characteristic umbilicated morphology and map external genital, pubic, perianal and adjacent lesions.
Interpretation and limitations
Typical multiple papules need no laboratory confirmation, but the examination must actively identify atypical or internal-site features.
02
Dermoscopy
Why
Demonstrate central pore, polylobular white material and peripheral vessels when naked-eye morphology is uncertain.
Interpretation and limitations
Supportive findings strengthen but do not replace biopsy when malignancy or another serious diagnosis remains plausible.
03
Histopathology
Why
Resolve an atypical, giant, solitary or treatment-resistant lesion.
Interpretation and limitations
Characteristic Henderson–Patterson bodies confirm molluscum; histology also detects keratoacanthoma, cancer or fungal mimic.
04
Fourth-generation HIV test
Why
Identify HIV when burden, distribution or persistence suggests immune suppression.
Interpretation and limitations
A negative laboratory result excludes acquisition only beyond its 45-day window; use RNA assessment for suspected acute HIV.
05
Site-specific STI screen
Why
Detect infections sharing the adult genital sexual exposure.
Interpretation and limitations
Choose chlamydia and gonorrhoea sampling sites from exposure and add syphilis, hepatitis and pregnancy assessment as indicated.

06Differential diagnosisRealistic alternatives and the features that help distinguish them.

Anogenital warts

HPV lesions are more papillomatous or rough and usually lack the smooth central umbilication of molluscum.

Folliculitis

Pustules centred on hairs, tenderness and shaving history indicate follicular inflammation rather than pearly viral papules.

Secondary syphilis

Condylomata lata are broad moist plaques with supportive systemic signs and treponemal serology. This distinction guides safe assessment and avoids unsupported changes to diagnosis, prophylaxis or treatment.

Keratoacanthoma

A rapidly growing crateriform solitary lesion can mimic giant molluscum and requires histological diagnosis. This distinction guides safe assessment and avoids unsupported changes to diagnosis, prophylaxis or treatment.

Fungal infection

Disseminated fungal papules in severe immune suppression can appear umbilicated and demand biopsy and culture. This distinction guides safe assessment and avoids unsupported changes to diagnosis, prophylaxis or treatment.

07ManagementImmediate care, first-line treatment, alternatives and escalation.

01Worked caseConfirm then offer observationFirst stepA healthy adult has several painless umbilicated papules confined to external pubic skin.

1Inspect the complete affected region with consent and verify classic morphology without ulceration, pigment or induration.
2Offer site-specific STI testing and explain that adult genital disease is often sexually acquired but cannot date transmission.
3Recommend expectant management as a safe first option and discuss avoiding scratching, shaving and shared razors.
4Provide review access if lesions spread, persist, inflame significantly or develop an atypical appearance.

02Active treatmentChoose a bounded local methodAn immunocompetent adult prefers removal after informed discussion of spontaneous resolution.

1Select cryotherapy for visible external lesions or consider carefully instructed podophyllotoxin where BASHH and product criteria are met.
2Protect normal skin, explain pain, blistering, erosion and pigment change, and treat limited areas per session.
3Reassess the diagnosis if response is absent rather than extending a damaging course indefinitely.

03PregnancyAvoid contraindicated topical therapyA pregnant patient requests treatment for external genital molluscum.

1Reconfirm diagnosis and explain that observation remains reasonable in uncomplicated disease.
2If removal is necessary, use clinician cryotherapy or cautery with appropriate expertise.
3Avoid podophyllotoxin during pregnancy and do not extrapolate genital-wart regimens to molluscum.

04Immune suppressionRestore immune controlDisease is giant, confluent, facial, disseminated or unusually persistent.

1Offer HIV testing and review transplantation, cancer treatment and immunosuppressive medicines.
2For advanced HIV, link urgently to ART because immune restoration is the main treatment for extensive disease.
3Use lesion-directed therapy with specialist input and exclude fungal, bacterial or malignant mimics when morphology is atypical.

Key medicines and prescribing safety3 treatments · regimens, roles and cautions

Patient-applied cytotoxic therapy can clear selected genital molluscum when active treatment is preferred.

Podophyllotoxin for selected external lesions

Apply the licensed 0.5% preparation only to suitable visible external lesions on the guideline-directed cycle after clinician instruction.

Avoid in pregnancy, internal mucosa and uncertain lesions; limit treated area and stop for severe erosion or systemic symptoms.

Reduces itch and scratching that otherwise promotes autoinoculation and secondary infection.

Mild topical corticosteroid for dermatitis

Apply a thin layer of a low-potency corticosteroid once or twice daily for a short course to eczematous surrounding skin.

Do not apply indiscriminately to infected broken skin or use potent steroid on genital tissue without specialist assessment.

Supports the skin barrier and reduces itch without attempting to destroy the viral papule.

Emollient

Apply a bland fragrance-free emollient to dry or eczematous surrounding skin as often as needed.

Avoid fragranced irritants and shared pots; new pain, pus or spreading erythema needs review rather than more emollient.

08ComplicationsImportant consequences, why they occur and why they matter clinically.

Molluscum dermatitis

Eczematous inflammation around lesions causes itch, scratching and broader autoinoculation across fragile skin. This distinction guides safe assessment and avoids unsupported changes to diagnosis, prophylaxis or treatment.

Bacterial superinfection

Excoriated lesions allow impetiginisation or cellulitis, especially when eczema or immune suppression impairs the barrier. This distinction guides safe assessment and avoids unsupported changes to diagnosis, prophylaxis or treatment.

Scarring and pigment change

Aggressive destruction, squeezing or secondary infection causes avoidable scars and post-inflammatory colour change. This distinction guides safe assessment and avoids unsupported changes to diagnosis, prophylaxis or treatment.

Psychosexual distress

Visible genital papules create stigma, transmission anxiety and avoidance of intimacy despite their benign natural history.

Marker of immune deficiency

Extensive adult disease may be the presenting clue to advanced HIV or another important immune disorder.

09Monitoring and follow-upTreatment response, safety checks and longer-term review.

Review only when requested for observation, while giving a route back for new distribution or diagnostic change.
After cryotherapy or topical treatment, assess healing, pain, ulceration, pigment change and whether untreated lesions remain.
Track dermatitis and scratching because barrier repair can reduce autoinoculation.
Confirm completion and results of indicated STI and HIV tests using their assay-specific windows.
In immune suppression, monitor lesion burden alongside viral load, CD4 recovery or the relevant immune treatment.
Biopsy a persistent atypical lesion rather than recording repeated failed molluscum treatment.

10Special situationsVariants, exceptions and circumstances that change the usual approach.

The central dell matters

A smooth pearly papule with umbilication is more typical of molluscum than the irregular surface of a wart.

Inflammation can mean clearance

A local red halo can accompany effective immune response and does not automatically indicate bacterial infection.

Observation is active care

Explaining natural history, skin care, transmission and return criteria makes non-treatment a supported clinical choice.

Shaving spreads locally

Razors create microtrauma and transfer viral material, often producing a line of new lesions.

Imiquimod is not recommended

Trials did not show useful benefit for genital molluscum and application reactions can add morbidity.

ART treats the host problem

For extensive molluscum in advanced HIV, immune restoration is more important than repeated destruction of individual lesions.

11Common pitfallsFrequent interpretation and management errors.

01
Do not confuse genital molluscum with warts, folliculitis, syphilis or skin cancer.
02
Do not assume a child with genital lesions acquired them sexually without a full specialist assessment.
03
Do not prescribe imiquimod as routine genital molluscum treatment.
04
Do not use podophyllotoxin during pregnancy or on mucosal or uncertain lesions.
05
Do not overlook advanced HIV in giant, facial or disseminated adult disease.
06
Do not shave, squeeze or curette lesions at home because this spreads virus and scars skin.

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