Athlete's foot is a dermatophyte (fungal) infection of the feet.
Tinea pedis is the most common dermatophytosis (see see Overview of Dermatophytoses (Ringworm, Tinea)) because foot sweating results in accumulation of moisture in the warm areas between the toes that allows fungi to grow. The infection may spread from person to person in communal showers and bathrooms or in other moist areas where infected people walk barefoot. People who wear tight shoes are also at risk. The infection is usually caused by Trichophyton.
The fungus can cause mild scaling with or without redness and itching. The scaling may involve a small area (particularly between the toes) or the entire sole of the foot. Sometimes scaling is severe, with breakdown and painful cracking (fissuring) of the skin. Fluid-filled blisters can also form. Over time, the skin on the soles may thicken. Because the fungus may cause the skin to crack, tinea pedis can lead to bacterial infection (see see Overview of Bacterial Skin Infections), especially in older people and in people with inadequate blood flow to the feet.
The diagnosis is usually obvious to doctors based on symptoms and the appearance of the affected area.
The safest treatment is using antifungal drugs that are applied directly to the affected area (topical). However, tinea pedis commonly recurs, and people often have to use antifungal drugs for a long time. Antifungal drugs taken by mouth, such as itraconazole and terbinafine, are effective but may have side effects. To possibly reduce recurrences, antifungal drugs can be applied to the skin.
Reducing moisture on the feet and in footwear helps prevent recurrences. Wearing open-toe shoes or shoes that “breathe” and frequently changing socks are important, especially during warm weather. Spaces between toes should be thoroughly towel-dried after bathing. To help keep the feet dry, people may apply antifungal powders (such as miconazole), gentian violet, or aluminum chloride solution or soak their feet in Burow solution (aluminum subacetate).
Last full review/revision June 2013 by Denise M Aaron, MD