The fungus Trychophyton lives on wet surfaces. But it thrives on human skin, particularly the feet, where it is responsible for the painful itching known as athlete’s foot that affects about 15 percent of the population. The name comes from the fact that a common place for transmission is locker rooms—the infected person showers, walks on the locker room floor, and deposits the fungus there, and then another person walks barefoot on the surface and picks it up, becoming infected. Once a person has acquired the fungus, it may be anywhere on the body that is warm and moist.
A type of ringworm, athlete’s foot produces itching between the toes and in other infected areas, as well as a scaly red rash and often ulcers and sores. It can easily spread to the hand if the sufferer scratches or picks at the itchy scales. One common variety of the condition causes dryness and scaling, resembling eczema, that starts on the soles of the feet and goes up the sides towards the ankles; this is known as "moccasin foot" or "plantar athlete’s foot." In addition, some people have an allergic reaction to the fungus that is separate from the effects of the infection.
In addition to walking barefoot in places like locker rooms and saunas, risk factors include tight shoes and damp socks, as well as sharing socks with someone who has been infected. Athlete’s foot fungus can even spread on carpets. It can easy to avoid, experts say, by such preventative measures as wearing sandals or shower shoes in places with damp surfaces; washing the feet regularly, drying them thoroughly, and keeping them dry; and rotating footwear and changing it regularly.
As is often the case with fungal infections such as ringworm, athlete’s foot can be difficult to treat, and is likely to require professional medical care. Keeping the feet clean and dry is a key factor, but an infected person’s towels should not be used more than once without being thoroughly washed until after the infection has cleared. Topical as well as oral anti-fungal medications are often prescribed to eliminate the Trychophyton fungus.