Warts are benign (not cancerous) skin growths that appear when a virus infects the top layer of the skin.  Viruses that cause warts are called human papillomavirus (HPV).  You are more likely to get one of these viruses if you cut or damage your skin in some way.  Wart viruses are contagious, though not everyone exposed to the virus will develop a wart and we aren't exactly sure why.

Meghan L.