Athlete's foot, also known as tinea pedis, is a common skin infection of the feet cause by a fungus. It often results in itching, scaling, and redness. In severe cases the skin may blister. In athlete's foot infection occurs most often between the toes. The bottom of the foot can also be affected. Fungal infection of the nails or the hands may occur at the same time. It is a member of the group of diseases known as tinea.