Anal Warts

Anal warts (condylomata acuminata) are benign epithelial growths of the perianal skin and anal canal caused by human papillomavirus, mainly types 6 and 11.

• Transmission is sexual (including receptive anal intercourse), by autoinoculation, and vertically at birth.
• Incubation is 3 weeks to 8 months; immunosuppression (HIV) increases burden, recurrence and malignant transformation.
• Incidence peaks at 20 to 24 years; high risk types 16 and 18 cause anal intraepithelial neoplasia and anal cancer.

Soft, flesh-coloured, pink or pigmented papules and cauliflower-like or flat lesions around the anus, perineum and within the canal.

• Itch, bleeding, discharge, discomfort, difficulty with hygiene, and sometimes pain if fissured.
• Large confluent lesions (giant condyloma) invade locally.
• Differential diagnosis: condylomata lata (secondary syphilis), molluscum contagiosum, skin tags, haemorrhoids, anal intraepithelial neoplasia, squamous cell carcinoma, seborrhoeic keratosis, Crohn disease skin tags, lichen planus.
• Complications: recurrence (25 to 50 percent), secondary infection, bleeding, anal canal obstruction, malignant transformation (squamous cell carcinoma), psychological distress, and transmission to the neonate (laryngeal papillomatosis).

Clinical inspection, digital rectal examination, proctoscopy to examine the canal, and high resolution anoscopy where available.

• Biopsy for atypical, pigmented, indurated, ulcerated, bleeding or treatment-resistant lesions, and in HIV.
• Screen for HIV, syphilis, hepatitis B, gonorrhoea and chlamydia.
• Acetic acid 5 percent application highlights flat lesions (whitening).
• HPV typing is not required.

Supportive: counselling on benign nature and recurrence, hygiene, condom use (reduces but does not eliminate transmission), partner assessment, smoking cessation.

Pharmacological (patient applied, external lesions):

• Podophyllotoxin 0.5 percent solution or 0.15 percent cream twice daily for 3 consecutive days then 4 days off, up to 4 cycles (maximum 0.5 mL daily, not on large areas).
• Imiquimod 5 percent cream three times weekly at night, washed off after 6 to 10 hours, for up to 16 weeks.
• Sinecatechins 10 percent ointment three times daily for up to 16 weeks.

Clinician applied:

• Trichloroacetic acid 80 to 90 percent applied weekly to small lesions, with powdered talc or sodium bicarbonate to neutralise excess.
• Cryotherapy with liquid nitrogen every 1 to 2 weeks.
• Podophyllin resin 10 to 25 percent weekly (wash after 1 to 4 hours).

Procedures: electrocautery, scissor or shave excision, laser ablation or infrared coagulation for intra-anal, extensive or resistant lesions; surgery under anaesthesia for giant condyloma, with biopsy of all excised tissue.

Special groups

• Pregnancy: avoid podophyllotoxin, podophyllin, imiquimod and sinecatechins; use trichloroacetic acid, cryotherapy or excision; caesarean delivery only for obstructing lesions.
• HIV: start or optimise antiretroviral therapy, lower threshold for biopsy, expect recurrence.
• Children: consider sexual abuse; refer to specialist services.

Prevention: HPV vaccination (9-valent), 2 doses at 0 and 6 months for ages 9 to 14 years, 3 doses at 0, 1 to 2 and 6 months for age 15 years and over and for immunosuppressed people.

Red flags: pigmentation, ulceration, fixation, bleeding, rapid growth, lesions unresponsive to 3 months of treatment.

Follow-up: review every 2 to 4 weeks during treatment and at 3 months; anal cytology and high resolution anoscopy surveillance in HIV positive and high risk patients.