Plantar warts are hard, grainy growths that usually appear on the heels or balls of your feet, areas that feel the most pressure. This pressure also may cause plantar warts to grow inward beneath a hard, thick layer of skin (callus). Plantar warts are caused by the human papillomavirus.
Plantar warts and Palmer warts are common, especially in children. These warts are named for where they appear on the body. Palmer warts occur on the hands, and plantar warts on the bottom of the foot.Virtually everyone will have a wart (or several) someplace at some time in their lives.
Plantar warts and palmer warts are noncancerous skin growths, caused by a viral infection in the top layer of the skin. The culprit is a strain of virus called human papillomavirus or HPV. Many strains of the virus exist, and those that cause common warts on the hands and feet are not the same strains of HPV that cause genital warts.