A wart is a viral infection, which can enter through a small cut or break in the skin. A wart is commonly seen on the bottom of the foot (plantar wart), but it can also appear anywhere on the foot or toes.
Warts may appear spongy, with tiny red, brown, or black spots. They can grow up to an inch or more across, and can occur alone (solitary) or with smaller warts clustered nearby (mosaic). It is also possible that the lesions mimic other growths, e.g., calluses or corns or more serious lesions, including carcinomas, melanomas, and sarcoma. They can persist for years, and reoccur in the same spot. If left untreated, warts can spread to other parts of the foot, to the hand, or other areas of the body. A wart will usually feel painful with side to side pressure.