Warts are non-cancerous skin growths caused by a viral infection in the top layer of the skin or mucous membranes. Viruses that cause warts belong to a "family" called human papillomavirus (HPV). The appearance of a wart depends on where it is growing. Warts are usually skin colored and feel rough to the touch, but can be dark, flat or smooth.
There are several different types of warts. The first one I am going to tell you about is called common warts. Common warts grow around the nails, on the fingers and on the backs of the hands. They are more common where skin has been broken, for example where fingernails are bitten or hangnails picked.
