Athlete's Foot is a contagious fungal disease. Although it generally is found on the feet due to its method of transmission, it can in fact be found in any part of the body which is often moist. If it is found in the groin, for example, the same infection is called jock itch.
The fungus that causes the disease thrives on wet surfaces, particularly showers. If a person has the infection, it will most likely be passed along to anyone who touches the same surface with bare skin. Because feet themselves often sweat, they also provide a perfect breeding ground once they are exposed to the fungus.
Athlete's Foot can usually be easily treated with non-prescription topical preparations, although severe cases often require a doctor's prescription for stronger treatment. However, prevention is usually more effective. If you are in an environment where Athlete's Foot is likely to be, make sure your feet are cleaned thoroughly after contact with the floor and that they are completely dry before you put on socks or shoes.
In One Day, One Room, House has some fun with a well groomed patient who had been using his toenail clippers to trim his nose hair and had inadvertently given himself the same fungus in his nose.