Firm, skin-coloured or darker growths on the skin caused by a viral infection

  • Most common in children and young adults
  • Warm, moist conditions are a risk factor
  • Gender and genetics are not significant factors

Warts, also called verrucas, are small growths caused by human papillomaviruses. The viruses invade skin cells and encourage them to multiply, thus creating thickened areas of skin. Warts usually occur on the hands or feet and are generally harmless. However, some types affect the genitals and are more serious (see Genital warts).

Warts are transferred by direct contact with an infected person or from virus particles on recently shed flakes of skin. The infection is commonly spread in warm, moist conditions.

Most people have at least one wart by the age of 20, but in some people warts recur. People with reduced immunity due to a disease such as AIDS (see HIV infection and AIDS) may develop large numbers of warts.

What are the types?

There are three main types of wart. These types are classified according to their appearance and the different sites on the body on which they occur.

Common warts

These warts most frequently occur on the hands. They are:

  • Firm with a rough, raised surface.

  • Usually round.

  • Dotted with tiny black spots.

The black spots are small blood vessels. Common warts often grow in groups, which are known as crops.

Plantar warts

These warts occur on the soles of the feet. Although plantar warts are the same as common warts, they grow into the skin because they are continually under pressure from the weight of the body. A group of plantar warts that have joined together is called a mosaic wart. Plantar warts are:

  • Flattened into the sole of the foot.

  • Firm, with a thickened surface.

  • Usually painful to walk on.

  • Dotted with tiny black spots.

The virus that causes plantar warts is usually picked up from walking barefoot in communal areas, such as changing rooms and swimming pools.

Appearance of a plantar wart

This wart on the sole of the foot has been flattened by the body’s weight and has developed a thickened surface.

Flat warts

Verruca plana, also known as flat warts, commonly occur on the wrists, backs of the hands, and face. Flat warts vary in size and are:

  • Skin-coloured.

  • Flat-topped and very slightly raised.

  • Often itchy.

These warts often occur in lines where the virus has spread along a scratch.

What might be done?

Most warts disappear without treatment, but this can take months or years. Many over-the-counter wart treatments are available (see Treating a wart). If a wart persists despite self-help measures or if you are unsure whether a lesion is a wart, consult your doctor. You should tell your doctor if a wart is painful, is on the face or genitals, or affects a child under the age of 5. The doctor may remove a wart by freezing, scraping, or burning it off. Sometimes, warts may recur.

Self-help: Treating a Wart

From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.

The subjects, conditions and treatments covered in this encyclopaedia are for information only and may not be covered by your insurance product should you make a claim.

Back to top