Warts

What it is

A wart is a skin growth caused by a DNA virus called the human papillomavirus (HPV). Its appearance varies with its type and its location on the body. Warts on the face may be smooth and flat-topped — plane warts — and they tend to spread rapidly with shaving. Warts on the limbs, common warts, may be flesh-coloured, raised and hard. Those on the soles of the feet, plantar warts, tend to grow deep into the skin and are more painful because of the weight put on them.

How it spreads

The virus gains entry into the skin after direct contact with recently shed viruses kept alive in warm, moist environments, or by direct contact with an infected person. The site of entry may be an area of recent injury. Once the virus enters the skin, a wart may appear on the surface any time between one and eight months later.

In some people warts resolve spontaneously. But while they are present they may spread from one part of the body to another by unintentional handling, and to close contacts. Plantar warts are very persistent, and so are warts in people whose immunity is reduced. Treatment is therefore useful in preventing spread.

How we treat it

Treatment depends on the site, the number and type of lesions, and the age of the patient. Several methods are available. The ones commonly used are wart paint — a combination of salicylic acid and lactic acid; cryotherapy, freezing with liquid nitrogen; and electrocautery, burning with an electric current after numbing the skin. Warts can recur after treatment at the same site or at different sites, and several treatments at frequent intervals may be required.

Warts and cervical cancer

All cervical cancers in women are caused by HPV, which also causes genital warts in both sexes. This does not mean that everyone who is infected will develop cervical cancer. Vaccination against HPV is available, and your doctor will advise on what is currently recommended. See the HPV vaccination page.