Athlete’s foot is a fungal skin infection that affects the feet, most commonly between the toes. About 3% of the world’s population has it at any given time, and the lifetime risk of getting it at least once is as high as 70%. It’s one of the most common skin infections in adults, caused by fungi that thrive in warm, moist environments like the inside of your shoes.
What Causes It
The fungi responsible for athlete’s foot are dermatophytes, organisms that feed on keratin, the protein that makes up your skin, hair, and nails. These fungi grow best in damp, enclosed spaces, which is why feet are such a common target. You pick them up by walking barefoot on contaminated surfaces like locker room floors, pool decks, and shared showers. Once on your skin, the fungi colonize the outermost layer and spread if conditions stay warm and moist.
Tight, poorly ventilated shoes create the ideal breeding ground. Sweaty socks that stay damp for hours give the fungus exactly what it needs. You can also spread it from foot to foot, or to other parts of your body, by touching an infected area and then touching somewhere else. Sharing towels or shoes with someone who has the infection is another common route.
Three Types and How They Look
Athlete’s foot doesn’t always look the same. It shows up in three distinct patterns, and knowing which one you have helps explain why your symptoms might not match someone else’s.
Interdigital
This is the classic version and the most common. It appears between the toes, usually between the fourth and fifth (the two smallest). The skin turns red, becomes soft and waterlogged-looking, and starts to crack and peel. Itching is the main complaint. If left alone, the cracks can deepen into painful fissures that open the door to bacterial infections.
Moccasin Type
This form covers the sole and sides of the foot in a pattern that looks like a moccasin shoe. The skin becomes thick, dry, and scaly, sometimes with a reddish tint underneath. It often affects both feet at the same time. Because it can look a lot like dry skin or eczema, many people don’t realize it’s a fungal infection. It tends to be chronic and harder to treat than the interdigital type.
Vesicular (Blister) Type
The least common form produces painful, itchy blisters, usually on the arch or the ball of the foot. The blisters are typically filled with clear fluid. If the fluid turns cloudy or pus-like, that’s a sign bacteria have moved in on top of the fungal infection. This type can flare up suddenly and may be confused with allergic reactions or other blister-forming skin conditions.
Conditions That Look Similar
Several other skin problems mimic athlete’s foot closely enough to cause confusion. Eczema on the feet, psoriasis, and contact dermatitis (a reaction to something your skin touched, like a material in your shoe) can all produce redness, scaling, and itching in the same areas. Bacterial infections can also cause peeling and cracking between the toes.
The key difference is that athlete’s foot is caused by a living organism that can be identified under a microscope. If a doctor suspects athlete’s foot but wants to confirm, they’ll gently scrape a small sample of skin from the affected area and examine it on a slide. Fungal infections show a characteristic pattern of branching, thread-like structures that other conditions don’t produce. This simple test takes minutes and can prevent weeks of using the wrong treatment.
How It’s Treated
Most cases of athlete’s foot clear up with over-the-counter antifungal creams or sprays applied once or twice daily. These products work by disrupting the fungal cell membranes, either killing the fungus outright or stopping it from growing. With consistent use, the infection typically resolves within two to four weeks.
The most common mistake is stopping treatment as soon as the itching fades. The fungus can still be present in the skin even after symptoms improve, and quitting early is a reliable way to get a recurrence. Follow the full treatment course listed on the packaging, even if your feet look and feel normal before you finish.
For moccasin-type infections or cases that don’t respond to topical treatment, a doctor may prescribe an oral antifungal medication. The typical course runs two to six weeks. Oral treatment is more effective at reaching the fungus embedded in thickened skin, but it’s reserved for stubborn cases because it can occasionally affect liver function.
What Happens if You Ignore It
Untreated athlete’s foot rarely resolves on its own. More often, it spreads. The fungus can move to your toenails, causing a thickened, discolored nail infection that’s significantly harder and slower to treat. It can also spread to your hands (especially if you pick at your feet) or to your groin, where the same type of fungus causes jock itch.
The more serious concern is bacterial infection. Cracked, broken skin between the toes is an open invitation for bacteria, particularly streptococcus. This can lead to cellulitis, a spreading skin infection that causes redness, warmth, pain, and swelling, sometimes accompanied by fever and chills. The CDC specifically identifies athlete’s foot as a risk factor for lower-leg cellulitis and recommends that people with recurrent cellulitis be checked and treated for fungal foot infections. Cellulitis requires antibiotics and, in some cases, hospitalization.
Prevention That Actually Works
The fungus needs moisture to survive, so keeping your feet dry is the single most effective prevention strategy. Wash your feet daily and dry them thoroughly, especially between the toes. This step alone makes a significant difference. Change your socks at least once a day, more often if your feet sweat heavily.
Rotate your shoes so each pair has at least a full day to dry out between wears. Choose shoes made of breathable materials when possible, and opt for moisture-wicking socks over cotton, which holds dampness against the skin. In shared wet environments like gym showers and pool areas, wear sandals or shower shoes.
If you’ve had athlete’s foot before, you’re more susceptible to getting it again. Keeping an antifungal powder or spray on hand for your shoes and feet during high-risk periods (hot weather, heavy exercise) can help prevent reinfection before it starts.