Warts are one of several soft tissue conditions of the foot that can be quite painful.
They are caused by a virus, which generally invades the skin through small or invisible cuts and abrasions. They can appear anywhere on the skin, but, technically, only those on the sole are properly called plantar warts. Most warts are harmless, even though they may be painful. The wart, however, is a viral infection. It is also possible for a variety of more serious lesions to appear on the foot, including malignant lesions such as carcinomas and melanomas.