Warts are non-cancerous skin growths caused by viral infection in the top layer of the skin or mucus membranes. Viruses that cause warts belong to a family called human papillomavirus (HPV). Also known as verruca, warts are usually skin colored and feel rough to the touch, but they can be dark, flat or smooth. There are several types of warts: common warts (around nails on the fingers and toes), foot warts (also called plantar warts and located on the soles of the feet), flat warts (flatter and smoother than other warts). Flat warts can grow in great numbers at any one time. Flat warts can be found on children’s faces, the beards of men, and legs of women-irritation from shaving could account for this spread.