Warts are most common in children and teens. But they can occur at any age. They are also more common in certain jobs, such as those that involve handling meat, poultry, or fish. A weakened immune system may make you more likely to have warts.

Warts are caused by the human papillomavirus (HPV). There are over 150 types of HPV. This virus can spread between people. But you can be exposed to the virus and not get warts. Warts tend to form where skin is damaged or broken. But they can also appear elsewhere. Left untreated, warts can grow in number. They can also spread to other parts of the body.

There are many types of warts. Some of the most common ones are described below:

• Common warts. These have a raised, rough surface. Enlarged blood vessels in the warts look like dots on the warts’ surface. Common warts form mainly on the hands, but can appear on other parts of the body.

• Plantar warts. These are warts on the soles of the feet. When you stand or walk, pressure makes plantar warts painful. When they form in clusters, plantar warts are called mosaic warts.

• Periungual warts. These form under and around fingernails. People who bite their nails are more at risk.

• Filiform warts. These are slender, fingerlike growths that can dangle from the skin. They most often appear on the face and neck.

• Flat warts. These are small, smooth growths. They tend to form in clusters on the face, backs of the hands, or legs.

• Genital warts. These can appear on or around the genitals. These warts can spread and are linked to cervical, anal, and other cancers. So it is important to have them treated quickly and to discuss these with sexual partners.