Athlete's foot is an infection of the feet caused by fungus. The medical term is tinea pedis. Athlete's foot may last for a short or long time and may come back after treatment.

The body normally hosts a variety of microorganisms, including bacteria and fungi. Some of these are useful to the body. Others may, under certain conditions, multiply rapidly and cause infections. Athlete's foot occurs when a particular type of fungus grows and multiplies in your feet (especially between your toes) or, less commonly, your hands.

Of the fungal infections known as tinea infections, Athlete's foot is the most common. It may occur at the same time as other fungal skin infections such as ringworm or jock itch. These fungi thrive in warm, moist areas. Your risk for getting athlete's foot increases if you:

• Wear closed shoes, especially if they are plastic-lined
• Keep your feet wet for prolonged periods of time
• Sweat a lot
• Develop a minor skin or nail injury

Athlete's foot is contagious, and can be passed through direct contact, or contact with items such as shoes, stockings, and shower or pool surfaces.

The most common symptom is cracked, flaking, peeling skin between the toes. The affected area is usually red and itchy. You may feel burning or stinging, and there may be blisters, oozing, or crusting. In addition to the toes, the symptoms can also occur on the heels, palms, and between the fingers.

If the fungus spreads to your nails, they can become discolored, thick, and even crumble.

See also: Fungal nail infection

The diagnosis is based primarily on the appearance of your skin. If tests are performed, they may include:

• Skin culture (fungi from flecks of skin are able to grow in the lab)
• Skin lesion biopsy (examination may show fungus under the microscope)
• Skin lesion KOH exam (skin scrapings in KOH show fungus under the microscope)