According to the U.S. National Library of Medicine, athlete's foot is a common infection caused by the tinea fungus. It is not serious. Symptoms include itching, burning and cracked, scaly skin between the toes. Tinea grows best in damp, dark and warm places, which is why it often develops between the toes. It can spread to the toenails, as well, making them thick and crumbly.
Athlete's foot can be contracted from damp surfaces, such as locker room floors... Treatments include over-the-counter antifungal creams for most cases and prescription medicines for more serious infections."