Warts are caused by an infection with the human papilloma virus (HPV). The virus causes an excess amount of keratin, a hard protein, to develop in the top skin layer (epidermis). The extra keratin produces the rough, hard texture of a wart.

Why do warts occur?

When the human papillomavirus (HPV) enters a cut in the skin, it causes a skin infection that forms warts. Warts are very contagious. The virus can spread from person to person or from different parts of the body through: Direct contact with a wart.

Do warts mean anything?

Most warts are harmless, and you don't need to do anything -- unless, of course, they're painful or embarrassing. Waiting for warts to go away could backfire, though: A wart might get bigger, new warts may appear, or you could give them to someone else.