Warts are small, rough lumps on the skin that are benign (non-cancerous). They often appear on the hands and feet.

Warts can look different depending on where they appear on the body and how thick the skin is. A wart on the sole of the foot is called a verruca. The clinical name for a verruca is a plantar wart.

Warts are caused by infection with a virus known as the human papilloma virus (HPV). HPV causes keratin, a hard protein in the top layer of the skin (the epidermis) to grow too much. This produces the rough, hard texture of a wart.

Types of warts

There are several different types of warts. The more common types include:

• common warts
• plantar warts (verrucas)
• plane warts
• filiform warts
• periungual warts
• mosaic warts

The appearance of each type of wart will depend on several factors:

• where it is located on your body
• the strain (type) of HPV that is responsible for the wart
• factors such as whether you have a weakened immune system
• whether you have rubbed or knocked the wart

See Warts and verrucas – symptoms for more information about each type of wart.

Who gets warts

Most people will have warts at some time during their life. However, they are more common in school children and teenagers than in adults.It is estimated that 4-5% of children and adolescents have warts.

Warts are uncommon in babies and occur in equal numbers between males and females.

People who have an increased risk of developing warts include those with weak immune systems, for example, following treatment for cancer or due to an illness such as HIV and AIDS, and those who have had an organ transplant. Around 50% of people who have had a kidney transplant develop warts within five years.

A type of wart that is known as a ‘butcher’s wart’ can sometimes develop on the hands of people who are regularly in contact with raw meat, fish or poultry for long periods of time. However, this type of wart is rare.

Genital warts

Like other types of warts, genital warts are caused by HPV. Genital warts are most commonly transmitted during sexual intercourse and other types of sexual activity, including oral sex.

Genital warts should not be treated at home using over-the-counter medicines. If you think you have genital warts, visit your GP or local sexual health clinic.

Outlook

Most warts disappear on their own without treatment, although treatment can help to get rid of them more quickly. Treatment may be recommended in cases where:

• the wart is causing you pain or distress
• there are associated risk factors, such as having a weakened immune system

Several treatment options are available to help treat warts and verrucas successfully. See Warts and verrucas – treatment for more information.

Contagious

Contagious is when a disease or infection can be easily passed from one person to another.

Immune system

The immune system is the body’s defence system. It helps to protect the body from disease, bacteria and viruses.