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Warts - anogenital

SNOMED: 237109002865 words•Updated 03/03/2026
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Exam Tips

  • OSCE diagnosis is clinical; biopsy only for atypical, pigmented, ulcerated, indurated/fixed, or uncertain lesions.
  • Perianal warts do not prove anal intercourse; do not overinterpret sexual history from site alone.
  • Always mention STI co-screening and HIV/syphilis testing in management stations.
  • State pregnancy safety clearly: avoid podophyllotoxin (contraindicated) and use specialist-directed alternatives.
  • In viva, separate low-risk HPV (6/11, wart-causing) from high-risk oncogenic HPV types to demonstrate depth.

Definition

Anogenital warts (condylomata acuminata) are benign epithelial proliferations caused by human papillomavirus, most often low-risk types 6 and 11, affecting genital, perineal, perianal, and sometimes intra-anal or lower genital tract mucosa. They are commonly asymptomatic but may cause itch, discomfort, bleeding, dyspareunia, or urinary/anal symptoms depending on site and size.

Pathophysiology

HPV enters through microscopic breaks in anogenital skin or mucosa and infects basal keratinocytes. Viral replication is linked to epithelial differentiation, producing acanthosis, papillomatosis, and hyperkeratosis that form visible exophytic lesions after a variable latent period (often months). Low-risk HPV types (especially 6/11) have limited oncogenic potential compared with high-risk types, but co-infection with oncogenic HPV can occur, so wart presence does not exclude cancer risk from other HPV strains. Local immunity strongly influences persistence and recurrence; lesions are often larger/more persistent in immunosuppression.

Risk Factors

  • Sexual skin-to-skin contact with a partner with clinical or subclinical HPV infection
  • Younger age and peak sexual activity (highest prevalence in people aged 20-24 years)
  • Earlier sexual debut
  • Multiple sexual partners/increased lifetime partner number
  • Immunocompromise (including HIV, iatrogenic immunosuppression)
  • Diabetes (associated with larger/coalescent lesions in some cases)
  • Possible autoinoculation or fomite-related spread (less common than sexual transmission)

Clinical Features

Symptoms

  • Often asymptomatic
  • Local pruritus, irritation, or discomfort
  • Pain if lesions are traumatised/friable
  • Contact bleeding (including from underwear friction)
  • Dyspareunia
  • Urinary stream distortion or terminal haematuria if meatal/distal urethral involvement
  • Anal irritation, discharge, or bleeding with perianal/anal canal disease

Signs

  • Soft, flesh-coloured/whitish/hyperpigmented or erythematous papules or plaques
  • Classically cauliflower-like exophytic lesions; may be broad-based or pedunculated
  • Non-hairy skin lesions tend to be soft/non-keratinised; hairy skin lesions tend to be firmer/keratinised
  • Usually <10 mm individually but may coalesce into large plaques
  • Typical distribution: introitus, foreskin/sulcus, penile shaft, perianal area
  • Atypical red flags needing biopsy: pigmented, ulcerated, indurated/fixed, bleeding atypical lesions
  • Image correlation: typical exophytic condylomata appearance (see Figure from page 154 in a standard STI/dermatology atlas used for OSCE revision)

Investigations

Clinical diagnosis by inspection of external genital and perianal areas:Typical verrucous/papillomatous lesions in characteristic anogenital sites
Brief sexual history and STI risk assessment:Identifies need for full STI screen and co-infection risk
STI screening (for example NAAT for chlamydia/gonorrhoea, HIV serology, syphilis serology as indicated):May detect concurrent STI; important because genital warts do not occur in isolation in all patients
Speculum examination when indicated:Assesses vaginal/cervical extension if introitus upper limit not visible or vulvovaginal symptoms present
Proctoscopy and digital anorectal examination when indicated:Assesses anal canal involvement when anal margin upper limit not visible or anal symptoms present
Meatoscopy (and occasionally urethroscopy):Defines meatal/distal urethral lesions; urethroscopy for proximal disease or urinary warning symptoms
Biopsy of atypical or diagnostically uncertain lesions:Excludes mimics such as intraepithelial neoplasia/carcinoma in situ
Pregnancy test where relevant before treatment selection:Alters management because several self-applied topical therapies are contraindicated/avoided in pregnancy

Management

Lifestyle Modifications

  • Refer to sexual health services where possible for comprehensive STI assessment and treatment planning
  • Explain natural history: spontaneous clearance is common (about 30% by 6 months), so watchful waiting is reasonable in selected patients
  • Advise avoidance of friction/trauma to lesions and not to shave/pick lesions
  • Use condoms to reduce (not eliminate) transmission risk; HPV can spread from uncovered skin
  • Offer reassurance about benign nature while addressing anxiety, stigma, and psychosexual impact
  • Encourage attendance for cervical screening/HPV vaccination as per UK programmes

Pharmacological Treatment

Patient-applied antimitotic

  • Podophyllotoxin 0.5% solution: apply twice daily for 3 consecutive days, then 4 days off; repeat weekly cycles for up to 4 weeks
  • Podophyllotoxin 0.15% cream: apply twice daily for 3 consecutive days, then 4 days off; repeat for up to 4 weeks

Best for external, soft non-keratinised warts; not licensed for anal canal/internal mucosal lesions. Contraindicated in pregnancy; avoid on broken skin; common adverse effects are local burning, pain, erosion, and inflammation.

Patient-applied immune response modifier

  • Imiquimod 5% cream: apply thinly 3 times weekly at night, wash off after 6-10 hours; continue until clearance or up to 16 weeks

Useful for external warts, including some keratinised lesions; causes local erythema/erosion and can exacerbate inflammatory dermatoses. Avoid/seek specialist advice in pregnancy due to limited safety data; avoid internal use unless specialist-directed.

Clinician-applied caustic/ablative topical

  • Trichloroacetic acid (for example 80-90% solution) carefully applied by trained clinician at intervals

Used when self-treatment unsuitable or in pregnancy under specialist care. Must protect surrounding skin; risk of chemical burns and ulceration if misapplied.

Surgical / Interventional

  • Cryotherapy (liquid nitrogen) for accessible external lesions
  • Electrocautery/diathermy ablation
  • Scissor or shave excision/curettage under local or general anaesthesia depending on burden/site
  • Laser ablation for extensive/refractory disease or anatomically difficult lesions
  • Specialist management for intra-anal, urethral, cervical, or extensive disease

Complications

  • Psychological distress, embarrassment, and sexual relationship impact
  • Persistent or recurrent lesions after treatment
  • Treatment-related pain, irritation, erosions, and post-inflammatory hypo/hyperpigmentation
  • Scarring (including hypertrophic scarring) after ablative/surgical procedures
  • Bleeding or secondary infection after destructive or surgical treatment
  • Coexisting high-risk HPV infection with independent risk of anogenital neoplasia

Prognosis

Overall prognosis is good: lesions are benign and many resolve spontaneously (around 10-30% within 3 months; about 30% by 6 months). Recurrence is common in the short term, especially with immunosuppression, but most HPV infections become undetectable within about 2 years.

Sources & References

💊BNF Drug References(4)

✅NICE Guidelines(1)

📖Textbook References(1)

  • Oxford Handbook of Clinical Diagnosis (Huw Llewelyn, Hock Aun Ang, Keir Lewis etc.) (Z-Library).pdf(pp. 428, 429)[context]

Sources

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