Athlete's foot, or "tinea pedis," is most often caused by a fungus called Trichophyton rubrum. Other types of fungus that can cause athlete's foot include Epidermophyton floccosum and Trichophyton mentagrophytes. These fungi invade the superficial layers of skin and cause scaling, redness, and itching.

The fungus that causes athlete's foot can be spread to other superficial layers of skin, although the fungus prefers warm, moist areas such as feet and inner thighs. Breaks in the skin and chafed areas also create favorable environments for fungal infection. It is rare to see the fungus infect areas that contain many sebaceous (oil) glands such as the face.

If you have athlete's foot that persists despite treatment with an over-the-counter antifungal cream, be sure to see a doctor for treatment.