Most athlete's foot occurs when someone comes into contact with fungi that create the infection, states WebMD. A variety of fungi grow on top of human skin, including the athlete foot fungi. It spreads when someone comes in contact with fungi through infected skin or damp, contaminated surfaces, such as public showers or locker room floors.
Some people carry and spread the athlete's foot fungus without developing symptoms, warns WebMD. Although doctors don't know why, some individuals are more susceptible to athlete's foot. Patients who have contracted the condition are at risk of getting it again.
Two types of athlete's foot develops quickly, usually infecting the toe webs or creating blisters, states WebMD. The toe web variety usually occurs between the fourth and fifth toes and creates skin that peels and cracks. Sometimes, a bacteria infection accompanies it, worsening the skin damage. Vesticular is the second fast-developing type of athlete's foot. Fluid-filled blisters under the skin form anywhere on the foot, but are found most often on the soles. Like the toe web variety, it can also be accompanied by a bacterial infection.
The second type of athlete's foot affects the outside edges of the foot, in a moccasin-like pattern, and is frequently more difficult to treat, reports WebMD. Skin on the sole or heal thicken and crack. In severe cases, toenails crack, crumble or fall off.