Athlete’s foot is caused by fungal spores that thrive in warm, moist environments and land on your skin through direct or indirect contact. You can pick it up by walking barefoot in a locker room, sharing a towel, or simply keeping your feet trapped in sweaty shoes for too long. The fungus responsible is remarkably hardy, and understanding exactly how it spreads makes it much easier to avoid.
The Fungus Behind the Infection
Athlete’s foot is caused by a group of fungi called dermatophytes, which feed on keratin, the protein that makes up the outer layer of your skin. These fungi produce enzymes that break down keratin, allowing them to invade the surface of your skin and set up an infection. The most common species worldwide is Trichophyton rubrum, which is especially good at evading your immune system. Its cell walls contain compounds that slow down the rate your skin sheds its outer cells, which is one of the body’s natural defenses against surface infections. The result is a chronic, stubborn infection that can linger for weeks or months if untreated.
Where People Pick It Up
The classic source is any shared surface that stays damp. Locker room floors, public showers, pool decks, and communal bathroom floors are prime breeding grounds. When someone with an active infection walks barefoot on these surfaces, they leave behind fungal spores. Those spores are then picked up by the next person who walks through.
What surprises most people is how long those spores survive. Fungal spores from Trichophyton species can remain infectious on surfaces for up to five years in the right conditions. That means even dry surfaces carry risk. Hotel room carpets, gym mats, and shared footwear can all harbor the fungus long after an infected person has come and gone.
Shared personal items are another common route. Towels, socks, shoes, and bed linens can all transfer the fungus. If someone in your household has athlete’s foot, sharing a bath mat or drying off with their towel is enough to pick it up.
How Your Shoes Create the Perfect Environment
Contact with fungal spores is only half the equation. The spores need warmth and moisture to grow, and your shoes provide both. Closed-toe shoes like sneakers and boots trap heat and sweat against your skin, creating conditions that let the fungus flourish. Tight-fitting shoes make things worse by reducing airflow and causing friction that can damage skin and nails, giving the fungus an easier entry point. Corns, calluses, and small cracks from pressure all become vulnerable spots.
The material of your shoes matters too. Synthetic materials like rubber and plastic don’t breathe, so moisture builds up faster than it can escape. Non-ventilated athletic shoes are some of the worst offenders, especially if you wear them for hours at a time or put them back on while they’re still damp from yesterday’s workout. Even water shoes can trap moisture if they don’t drain well.
Who Gets It Most Easily
Anyone can get athlete’s foot, but certain factors raise your risk significantly. People who sweat heavily from their feet, wear the same pair of shoes daily without letting them dry out, or spend a lot of time in communal wet areas are the most likely to develop it. Athletes and military personnel get it at higher rates simply because of how much time their feet spend in closed, damp footwear.
Your immune system also plays a role. People with diabetes or other conditions that weaken immune function are more susceptible to infection and more likely to develop complications. In people with diabetes, athlete’s foot can progress to cellulitis, a serious bacterial skin infection that occurs when fungi crack the skin open and bacteria move in.
How It Spreads to Other Body Parts
One of the most underappreciated risks of athlete’s foot is that it doesn’t stay on your feet. The same fungi cause jock itch when they reach the groin and ringworm when they reach other areas of skin. The transfer happens easily: touch your infected foot, then touch your groin or another body part, and you’ve moved the fungus along. It can also travel through clothing. If you pull underwear on over infected feet, the fabric picks up spores and deposits them in the groin area.
A simple habit that reduces this risk: put your socks on before your underwear when getting dressed. This creates a barrier between your infected skin and the clothing that contacts your groin.
What It Looks and Feels Like
The infection most commonly starts between the toes, especially the fourth and fifth toes where moisture collects. The hallmark symptom is itching, often accompanied by burning, redness, and scaling skin. Some types cause fluid-filled blisters. Others cause the skin on the sole of your foot to thicken and crack, sometimes covering the entire sole in a dry, scaly rash that people mistake for simple dry skin.
Athlete’s foot is frequently confused with eczema on the feet, since both cause itchy, red, flaky skin. The key differences: eczema tends to appear in multiple areas of the body at once and goes through cycles of flaring and improving. It often starts in childhood. Athlete’s foot is more localized, usually starting between the toes, and it doesn’t go into remission on its own. If you have a persistent, itchy rash isolated to your feet, especially between the toes, fungal infection is the more likely explanation.
Practical Ways to Reduce Your Risk
Prevention comes down to two things: avoiding contact with spores and keeping your feet dry. Wear sandals or flip-flops in locker rooms, public showers, pool areas, and hotel rooms. Don’t share towels, socks, or shoes with anyone, and wash bath mats regularly if someone in your household is infected.
For your footwear, rotate between at least two pairs of shoes so each pair gets a full day to dry out. Choose shoes made from breathable materials like leather or mesh rather than synthetic plastics. Moisture-wicking socks help pull sweat away from your skin, and changing your socks midday makes a real difference if your feet sweat heavily. After showering or swimming, dry your feet thoroughly, especially between the toes, before putting on socks or shoes.