What Is Athlete’s Foot? Symptoms, Causes, Diagnosis, Treatment, and Prevention

Athlete’s foot, or tinea pedis, is a type of fungal infection of the feet. It’s also known as ringworm of the foot (the medical name for ringworm is tinea).

It typically occurs in people whose feet have become sweaty while wearing tight-fitting shoes.

The most common symptoms of athlete’s foot include a scaly rash that usually causes an itching and burning sensation around the affected area, often between the toes.

Athlete’s foot causes several symptoms that affect the feet, including:

• Red and itchy skin
• Mild scaling of the skin, which may cover small areas or the entire sole of the foot
• Painful cracking (fissuring) of the skin, typically a result of severe scaling
• Fluid-filled blisters
• Thickening of the soles of the feet

The fungal infection can also spread to the toenails, causing them to discolor, thicken, or crumble.

Athlete’s foot can damage the skin and leave it open for bacterial infections, such as cellulitis, to develop.

If you develop a rash on your foot that doesn’t improve within two weeks of starting self-care with an over-the-counter antifungal ointment or spray, talk to your doctor.

These symptoms can be a sign of a secondary infection that could spread and cause serious health complications.

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Athlete’s foot may be caused by several different types of fungi, including yeasts.

Most commonly, fungi called dermatophytes — which require keratin for growth and frequently lead to skin diseases — can cause the foot infection.

Dermatophytes also cause the skin infections ringworm and jock itch.

In the case of athlete’s foot, the fungi grow in the top layer of skin (the epidermis) and first enter the skin through small cracks.

The microbes require moisture and warmth to grow and spread.

Athlete’s foot is contagious, so it’s possible to get the infection from touching the affected skin of someone who has it, even if they don’t have an active case.

In addition, you can get athlete’s foot if you have poor hygiene, such as if you:

• Don’t wash and dry your feet after exercising, or after your feet get wet (including from sweat)
• Wear damp socks or tight-fitting shoes
• Share mats, rugs, bed linens, clothes, or shoes with someone who has it
• Walk barefoot in public areas, such as locker rooms, saunas, swimming pools, and showers

Your doctor may be able to diagnose athlete’s foot simply by looking at it.

The diagnosis can also be confirmed by your doctor by taking a thorough patient history.

• A KOH test
• A skin culture
• A skin biopsy

In a KOH test, your doctor will use the flat edge of a blade to scrape samples from your skin and examine them under a microscope. Then a solution containing potassium hydroxide (KOH) is added to the samples to dissolve the cellular material to reveal any fungi.

For a skin culture, your doctor will use a cotton swab to collect a sample from the affected area for lab testing.

A skin biopsy can also be used to identify the specific fungus causing your athlete’s foot. It’s also usually performed in your doctor’s office, under local anesthetic.

It usually takes about two weeks to receive results for these tests.

Prognosis of Athlete’s Foot

Athlete’s foot usually responds well to self-care, although it can come back.

If you have a health condition that places you at increased risk for infections — such as diabetes — long-term treatment with antifungal medication and preventive measures may be necessary.

The infection can also spread to the toenails, causing them to crack.

Your athlete’s foot symptoms should go away within two to four weeks of self-care. However, if they don’t, talk to your doctor.

You should also talk to your doctor immediately if your foot becomes swollen and warm to the touch or if you see red marks or pus or experience pain or fever. These are signs of a possible bacterial infection.

Medication Options

OTC antifungal creams, gels, lotions, sprays, and powders for athlete’s foot should contain one of the following active ingredients:

• clotrimazole
• miconazole
• oxiconazole
• ketoconazole

Your doctor may also recommend prescription oral antifungal medicines — examples include terbinafine (Lamisil) or itraconazole (Sporanox) — or oral antibiotics for any bacterial infections that may develop.

There are also prescription topical creams designed to kill the fungus that causes athlete’s foot.

Alternative and Complementary Therapies

For athlete’s foot, some people swear by home remedies such as tea tree oil or footbaths that contain certain herbal products. However, there have been very few studies evaluating the effectiveness of these remedies for athlete’s foot, and what few exist have yielded conflicting results.

Prevention of Athlete’s Foot

• Keeping feet clean and dry
• Washing your feet with soap after exercising
• Avoiding wearing heavy, closed shoes or thick socks
• Changing socks often
• Making sure socks are washed between uses
• Using antifungal foot powder on feet and in shoes
• Wearing flip-flops in gym showers or locker rooms to avoid contact with fungi
• Airing your feet out by taking your shoes off, or wearing sandals, as often as possible
• Avoiding public swimming pools and public showers
• Not sharing with others items used during exercise (equipment, towels, etc.)

Try wearing only cotton socks, which are more effective at absorbing sweat. If possible, choose footwear made with breathable materials, such as leather. Shoes made of vinyl and similar materials can retain sweat and create an environment for fungi to grow. When you’re doing laundry, consider using hot water and bleach, which can kill fungi in ways detergent can’t.

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Athlete’s foot infection can spread to other parts of your body, such as:

• Your hands
• Your toenails
• Your groin

If you scratch or pick at the infected areas of your feet, you run the risk of developing a similar infection on your hands.

Finally, the condition known as jock itch may be caused by the same fungus responsible for athlete’s foot, and it’s common for the infection to spread from the feet to the groin via your hands or a towel.

The affected area of your foot can also become infected with bacteria in addition to fungus. If this occurs, your foot may become red or swollen and you may experience pain.

If you develop these symptoms, call your doctor immediately.

Athlete’s foot is believed to be more common in men than in women, although there are no exact statistics for prevalence based on gender.

Athlete’s foot is closely related to other fungal infections, including ringworm and jock itch.

Ringworm of the body (also called tinea corporis) doesn’t come from a worm. It appears as a red and itchy rash that takes the shape of a circle with clearer skin in the middle — hence the name.

Ringworm spreads by direct skin-to-skin contact with an infected person or animal, including household pets. Mild ringworm usually responds to antifungal medications applied to the skin, but more severe infections may need treatment with prescription oral medications.

Similarly, jock itch (also called tinea cruris) is a fungal infection that causes an itchy rash in areas of your body, such as your groin, that tend to be warm and moist. Although often uncomfortable, it usually isn’t serious.

The American Orthopaedic Foot & Ankle Society maintains FootcareMD.org, a site that provides comprehensive information on a variety of conditions affecting the feet (it also includes a symptom checker).

The American Podiatric Medical Association’s site is another trustworthy source of information on conditions affecting the feet, such as diabetes.