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MRCGP hot topics - Genital warts

The first attack of anogenital warts is the most common STI diagnosis made by GUM clinics in the UK.

The first attack of anogenital warts is the most common STI diagnosis made by GUM clinics in the UK.

In 2005 over 80,000 new diagnoses were made, with the highest groups being 20 to 24-year-old males and 16 to 19-year-old females.

The diagnosis of warts carries much psychological and emotional distress and the ability to counsel patients is vital. Warts are caused by the human papilloma virus (HPV). There are over 90 known types of HPV; types 6 and 11 are often implicated in causing visible genital lesions. These are different from other oncogenic types of HPV .


The issue of how a person caught genital warts is often of considerable concern and distress. The incubation period is a minimum of six weeks but it is not possible to say the maximum time the virus can be incubated for. Transmission is most likely when warts are present; that said there is some suggestion that there is also asymptomatic viral shedding.

The use of condoms should be advocated to reduce the risk of transmission, however they will not be 100% effective as areas not covered by a condom will continue to have skin-to-skin contact.


Patients will complain of having found a lump. Often there is some itching. Warts are most commonly found around the interoitus and frenulum; perianal lesions are also common and anal intercourse is not necessary for them to occur at this site. Warts may be multiple or single and may or may not be keratinised.

Lesions can be flat, broad based or pedunculated. Diagnosis is made clinically by inspection of the areas. Molluscum can confuse the inexperienced clinician. All patients should be offered STI screening for other infections including a syphilis and HIV blood test.


There are a number of treatments for which there is little evidence to support the superiority of one over another. Treatment should be based on patient preference, previous treatments and the number, distribution and morphology of the warts. Recurrence could occur with any treatment but all should be applied correctly and for a full course before being deemed to have failed.

• Cryotherapy

Liquid nitrogen spray. Causes cytolysis, resulting in necrosis. Should be applied until a halo of freezing of a few millimetres around each lesion is achieved. Treatment is usually weekly.

• Podophyllotoxin 0.15%

Applied bd for three consecutive days, followed by four days of rest. Used as home treatment and then reviewed after four cycles. Rarely causes localised ulcerative reaction. May be continued if tolerated and reviewed on a monthly basis.

• Imiquimod

Induces local cytokines and therefore patients should be warned to expect erythema, but if sores or ulceration appear treatment should be stopped. It should be applied once daily on three alternate days of the week (for example, Monday, Wednesday, Friday) for up to 16 weeks.

Neither of the cream treatments are licensed for use in pregnancy or where there is a risk of the patient becoming pregnant. Patients should be counselled to this extent.

Genital warts are an extremely common and distressing STI. Counselling and providing information to patients is as important (if not more) as treating the lesions. GPs with some experience should be able to initiate treatment and offer patients screening for other infections.

Dr Andrew Perry is a GP registrar in Sheffield

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