Warts are growths of the skin and mucous membranes (the mouth or genitals) that are caused by over 100 types of the human papillomavirus (HPV). Common warts are usually found on areas of the body prone to trauma, such as the elbows, knees, and hands. The virus causes thickening of the top skin layer. They are usually painless and go away on their own, sometimes taking a few months to resolve, but can take up to two years.
Warts are usually acquired from person-to-person contact. The virus is not highly contagious but can cause an infection by entering through a small break in the skin. In the same way, warts can be spread to other places on your own body. The virus is rarely transferred by touching an object used by an infected person.[/ultimate_heading]
Warts can affect people of any age, but they are most common between the ages 12-16. It is estimated that 20% of schoolchildren and about 10% of the general population have warts. Those with HIV, organ transplants, or on chemotherapy have a higher incidence of warts due to their weakened immune system.