Warts (common, flat & plantar) - including symptoms, treatment and prevention

Warts are lumpy growths in the skin caused by infection with human papilloma viruses, of which there are now more than 100 known types. Papilloma viruses which cause warts in humans infect only humans and occur worldwide. Animals have their own types of wart viruses, but these cannot infect people. Different types of papilloma virus tend to infect different areas of the body (see also genital warts).

How warts are spread

The wart virus is thought to be transmitted by direct skin to skin contact or by contact with contaminated surfaces, for example floors.  

Signs and symptoms of warts

Common warts

Develop on the skin of children and adolescents and mainly occur on the knuckles, the backs of the hands and the knees. Occasionally such warts appear as a group.

Flat warts

Are flat-topped and are most common on the face and the back of the hands.

Plantar warts

Occur on the soles of the feet and occasionally on the palms of the hands. They are found most commonly in older children and adolescents.

Diagnosis of warts

Diagnosis is usually made by examination of the growth, but occasionally a doctor may request a scraping or biopsy.

Incubation period

(time between becoming infected and developing symptoms)

2 to 3 months, but ranging from 1 to 20 months.

Infectious period

(time during which an infected person can infect others)

Unknown, but at least as long as visible warts persist.

Treatment for warts

About 65% of warts will go away by themselves within 2 years. If treatment is necessary, the following may be used:

  • liquid nitrogen
  • chemical paint applications
  • surgical removal
  • laser therapy.

Prevention of warts

  • Exclusion from childcare, preschool, school or work is not necessary
  • avoid direct contact with warts. 
  • wear shoes
  • wash hands after any contact with warts.

Useful links