Anogenital Warts
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Direct answer
Anogenital warts, or condylomata acuminata, are soft, fleshy, papillomatous lesions caused by human papillomavirus, and the great majority are due to low-risk types 6 and 11. They are multiple, moist and cauliflower-like, and they occur on the external genitalia and perianal skin. Their treatment removes the visible lesions, which can be done by patient-applied creams or by clinic procedures, but it does not eliminate the virus, so recurrence is common.
What you must remember
- Low-risk types: HPV 6 and 11 cause most anogenital warts and are rarely linked with malignancy.
- High-risk types: HPV 16 and 18 are the main oncogenic types, associated with cervical, anal, penile, vulvar and oropharyngeal cancers.
- Morphology: soft, pink to flesh-coloured, cauliflower-like papules that are often multiple and moist, not hard keratotic lesions.
- Patient-applied therapy: podophyllotoxin 0.5 per cent or imiquimod 5 per cent cream is applied by the patient for small external warts.
- Clinic therapy: trichloroacetic acid 80 to 90 per cent or cryotherapy with liquid nitrogen is applied by a clinician, and both are preferred in pregnancy.
- Surgical therapy: electrocautery, excision or CO2 laser is used for extensive, large or refractory disease.
- Prevention: the quadrivalent HPV vaccine covers types 6, 11, 16 and 18, and the nonavalent vaccine adds types 31, 33, 45, 52 and 58.
A pathway for choosing treatment
The choice of therapy depends on the number, size and site of the warts, and on whether the patient is pregnant. The steps below follow the sequence an examiner expects.
- Confirm the diagnosis: most warts are diagnosed by inspection, but biopsy is needed when a lesion is pigmented, indurated, ulcerated or unusual, especially in an immunosuppressed patient.
- Assess the lesion and site: count the warts, measure them and note whether they lie in a moist or inaccessible area such as the urethral meatus or anal canal.
- Offer patient-applied therapy: podophyllotoxin or imiquimod is suitable for small external warts, and the patient applies it at home under instruction.
- Offer clinic-applied therapy: trichloroacetic acid or cryotherapy is used for warts in moist sites, and these are the preferred options in pregnancy.
- Excise large or refractory lesions: electrocautery, surgical excision or CO2 laser treats extensive disease that has failed topical therapy.
- Counsel and screen: partners are advised to attend, vaccination is offered, and women are referred for cervical screening because HPV is also linked to cervical cancer.
Where the exam plants its traps
Stems on anogenital warts test the HPV types, the pregnancy rules and the limits of treatment.
- Trap: treating anogenital warts with podophyllin in pregnancy Correct: podophyllin and podophyllotoxin are avoided in pregnancy, and trichloroacetic acid or cryotherapy is preferred.
- Trap: assuming HPV 6 and 11 cause cervical cancer Correct: these are low-risk types, whereas HPV 16 and 18 are responsible for most cervical cancers.
- Trap: believing that removing the warts eradicates HPV Correct: treatment clears visible lesions, but the virus may persist, so recurrence is common.
Frequently asked questions
Which HPV types cause most anogenital warts?
HPV types 6 and 11 cause the great majority of anogenital warts, and they are classed as low-risk because they are rarely linked with cancer. Types 16 and 18 are high-risk and are associated with cervical and anal cancers rather than typical warts.
Which HPV types are high-risk for cancer?
HPV types 16 and 18 are the main high-risk types for anogenital cancer, and they are responsible for most cervical cancers. They are also linked to anal, penile, vulvar and oropharyngeal cancers.
Which treatment for anogenital warts is safe in pregnancy?
Trichloroacetic acid and cryotherapy with liquid nitrogen are the preferred treatments for anogenital warts in pregnancy. Podophyllin and podophyllotoxin are avoided in pregnancy because of concerns about systemic absorption.
Which vaccine protects against the HPV types causing anogenital warts?
The quadrivalent HPV vaccine protects against HPV types 6, 11, 16 and 18, while the nonavalent vaccine extends coverage to types 31, 33, 45, 52 and 58. Vaccination reduces genital warts as well as the cancers linked to the high-risk types.
What is the first-line patient-applied treatment for anogenital warts?
Podophyllotoxin 0.5 per cent solution or imiquimod 5 per cent cream is applied by the patient at home for small external warts. The clinician chooses between them based on the site, the patient's preference and whether the patient is pregnant.