Athlete's foot is a skin infection caused by fungus. A fungal infection may occur on any part of the body; on the foot, it is called athlete’s foot, or tinea pedis. Fungus commonly attacks the feet because it thrives in a dark, moist and warm environment, such as a shoe or boot.
Fungal infections are more common in warm weather when feet tend to sweat more. Fungus thrives in damp areas, such as swimming pools, showers and locker rooms. Many workers often have sweaty feet and use facilities where fungus is commonly found, thus the term "athlete's foot."