Warts are skin growths that are caused by the human papillomavirus (HPV). There are more than 100 kinds of HPV, some of which can cause warts on the skin. HPV stimulates quick growth of cells on the skin’s outer layer. In most cases, common warts appear on the fingers, near the fingernails, or on the hands. Certain types of HPV can cause warts to appear in the genital area.

Warts are caused through direct contact with HPV, which is contagious. HPV may spread by person-to-person contact or through direct contact with an object used by a person with the virus. The virus that causes warts also can spread to other places on the body of the person with warts.

WebMD. (2009, September 18). Retrieved from https://www.webmd.com/skin-problems-and-treatments/warts