It typically occurs in people whose feet have become sweaty while wearing tight-fitting shoes. Athlete’s foot causes several symptoms that affect the feet, including:
Red and itchy skinMild scaling of the skin, which may cover small areas or the entire sole of the footPainful cracking (fissuring) of the skin, typically a result of severe scalingFluid-filled blistersThickening 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.
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 shoesShare mats, rugs, bed linens, clothes, or shoes with someone who has itWalk barefoot in public areas such as locker rooms, saunas, swimming pools, and showers
The diagnosis can also be confirmed by your doctor by taking a thorough patient history.
A KOH testA skin cultureA skin biopsy
In a KOH test, your doctor will use a needle or another tool 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. 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.
ClotrimazoleMiconazoleOxiconazoleKetoconazole
Your doctor may also recommend prescription oral antifungal medicines — examples include terbinafine or itraconazole — 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 dryWashing your feet with soap after exercisingAvoiding wearing heavy, closed shoes or thick socksChanging socks oftenMaking sure socks are washed between usesUsing antifungal foot powder on feet and in shoesWearing flip-flops in gym showers or locker rooms to avoid contact with fungiAiring your feet out by taking your shoes off, or wearing sandals, as often as possibleAvoiding public swimming pools and public showersNot 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.
Your handsYour toenailsYour 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. 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 Podiatric Medical Association’s site is another trustworthy source of information on conditions affecting the feet, such as diabetes.
