Aetiology and natural history
Anogenital warts are benign lesions caused by the human papillomavirus (HPV).
HPV infection is very common and most infections do not result in visible genital tract lesions.
Transmission is most often via sexual contact.
HPV preventative vaccination was introduced in 2008 for girls aged 12-13. Currently the quadrivalent vaccine (HPV 6/11/16/18) is being used in UK.
Single or multiple lumps
Irritation or discomfort
Rarely, secondary infection or maceration
Commonly warts present as soft cauliflower-like growths of varying size but can be flat, plaque-like or pigmented. Lesions on moist, non-hair bearing skin tend to be soft and non-keratinised and those on dry and hairy skin, firm and keratinised. Lesions may be broad based or pedunculated.
Warts can occur at any genital or peri-genital site and are common at sites of trauma. Asymptomatic lesions may be seen on the vagina, cervix, urethral meatus and anal canal.
Extra-genital lesions caused by genital HPV types may be seen in the oral cavity, larynx, conjunctivae, and nasal cavity; their management is beyond the scope of this guideline.
Rarely, warts may grow more rapidly and infiltrate local tissue or cause local erosion (Buschke-Lowenstein lesion).
Usually a clinical diagnosis is made from recognition of characteristic lesions. Rarely, biopsy may be required to confirm the diagnosis in atypical lesions or in cases that do not respond to treatment.
Examination should include the external anogenital and surrounding skin under good illumination. Magnification may be helpful for small lesions or where the diagnosis is uncertain.
Extra-genital sites should be examined if clinically indicated.
Classify warts as to morphology and record lesions on genital maps to aid assessment of response to treatment.
Some patients present with intraepithelial neoplastic lesions, with or without coincidental benign warts. Diagnosis of this is through biopsy. Features which may raise suspicion include:
Treatment choice depends on examination findings and patient preference. No treatment may be an option as one third of patients will clear warts spontaneously. All treatments have significant failure and relapse rates, and can cause local skin reaction. Use of a clinic algorithm has been shown to improve clinical outcomes.
Soft non-keratinised warts respond well to podophyllotoxin and trichloroacetic acid (TCA). Keratinised lesions may be better treated with physical ablative methods such as cryotherapy, excision, TCA or electrocautery. Imiquimod is suitable treatment for both keratinised and non-keratinised warts.
People with small numbers of low volume warts, irrespective of type, can be treated with ablative therapy or topical podophyllotoxin from the outset. Very large lesions should be considered for surgical treatment.
Electrosurgical and laser techniques may generate smoke containing HPV DNA. Masks and adequate extraction should be utilised during procedures. (IIb, B)
These are not licensed for the treatment of existing HPV infection, or HPV-associated disease.
Review is recommended at the end of a treatment course. If side effects or <50% response to treatment it is suggested that a second modality of treatment is applied. (IV, C)
Treatment options include no treatment, cryotherapy, electrosurgery and TCA.
Podophyllotoxin has been used <2cm2 (not licensed).
Colposcopy is not routinely recommended unless diagnostic uncertainty.
Treatment options include no treatment, cryotherapy, electrosurgery, TCA, laser ablation or excision.
If treated, repeat examination following treatment to confirm resolution.
Base of lesion visible - treat with cryotherapy, electrosurgery, laser ablation, podophyllotoxin or imiquimod.
Deeper lesions - surgical ablation under direct vision, which may require urology referral or use of a meatoscope.
Treatment options include cryotherapy, topical imiquimod (unlicensed indication), electrosurgery, laser ablation and TCA.
Treatment is not always warranted but aims to minimise the number of lesions present at delivery to reduce neonatal exposure to HPV.
Caesarean section is not indicated to prevent vertical transmission. Rarely it may be indicated if gross cervical warts or obstructive lesions are present.
Podophyllotoxin and 5-fluorouracil are teratogenic. Imiquimod is not approved for use in pregnancy as no data are available.
Cryotherapy, excision and ablative methods are safer options in pregnancy.
Imiquimod: no specific advice in SPC
Podophyllotoxin: not recommended
Children and adolescents
See BASHH guideline on children and young people. General management principles remain the same.
Lower response and increased relapse rates following treatment.
Longer treatment courses may be required, and patients should be carefully followed up.
No other modification of treatment recommendations is required.