Jock itch is a fungal skin infection that develops in the warm, moist folds of the groin, inner thighs, and buttocks. Known medically as tinea cruris, it’s caused by the same type of fungi responsible for athlete’s foot and ringworm. It’s three times more common in men than in women, largely because of the anatomy of the male groin, which traps heat and moisture against skin folds where fungi thrive.
What Causes the Infection
Two species of dermatophyte fungi are most often responsible: Trichophyton rubrum and Trichophyton mentagrophytes. These organisms feed on keratin, the protein that makes up the outer layer of your skin. They grow fastest in dark, damp environments, which is why the groin is such a common target.
One of the most common ways men develop jock itch is by spreading it from their own feet. If you have athlete’s foot and pull on underwear over your bare feet, you can transfer the fungus directly to your groin. Sharing towels, clothing, or sports equipment with someone who has an active infection is another route. The fungus can also linger on gym surfaces, locker room floors, and shower stalls.
Who Is Most at Risk
Wearing tight-fitting or wet clothing is the single biggest everyday risk factor. Athletic supporters, compression shorts, and damp underwear left on after a workout all create the conditions fungi need. Hot, humid climates make the problem worse, and jock itch is more common worldwide in tropical regions.
Beyond clothing and environment, certain health conditions increase susceptibility. Obesity creates deeper skin folds that trap moisture, and diabetes weakens the body’s ability to fight off fungal overgrowth. The prevalence of both of these risk factors is rising, including among younger men and adolescents.
What the Rash Looks and Feels Like
Jock itch typically starts as a patch of irritated, discolored skin along the crease where the inner thigh meets the groin. Depending on your skin tone, the rash may appear red, purple, gray, tan, or white. It often spreads outward in a ring-shaped pattern, with a raised, scaly border and clearer skin toward the center. Tiny bumps or blisters sometimes line the outer edge of the ring.
The skin inside the rash tends to look flaky or scaly. Itching ranges from mild to intense and usually gets worse with sweating or friction from clothing. The rash rarely crosses onto the scrotum itself, which is a helpful clue for telling it apart from other groin conditions. It can, however, spread to the buttocks and lower abdomen if left untreated.
Conditions That Look Similar
Several other skin problems mimic the appearance of jock itch, and treating the wrong one can make things worse. Inverse psoriasis, for example, causes smooth, shiny, discolored patches in skin folds that can look a lot like a fungal rash. The key difference is that psoriasis is an immune system disorder, not an infection, and it’s not contagious. If you apply a steroid cream (a standard psoriasis treatment) to what turns out to be a fungal infection, the fungus can actually spread faster.
Erythrasma is a bacterial infection that also targets skin folds and produces flat, brownish patches. It’s easily confused with jock itch but won’t respond to antifungal creams. Yeast infections caused by Candida can also affect the groin, particularly in men with diabetes, and tend to produce bright red patches with small satellite spots around the edges rather than the ring-shaped border typical of jock itch. If a rash isn’t improving after a couple of weeks of antifungal treatment, it’s worth getting a proper diagnosis rather than continuing to guess.
How It’s Treated
Most cases of jock itch clear up with over-the-counter topical antifungal creams or sprays. A large Cochrane review found that terbinafine and clotrimazole are both significantly more effective than placebo, with terbinafine showing especially strong results for clinical cure. Naftifine, another common OTC option, performed well for both killing the fungus and clearing visible symptoms. All three are widely available in drugstores.
The most important thing about treatment is duration. Many men stop applying the cream as soon as the itching fades, which is almost always too soon. The fungus can survive beneath skin that looks and feels normal. Continue applying the antifungal for at least one to two weeks after the rash has visibly cleared to prevent it from bouncing back. If the infection is widespread, doesn’t respond to topical treatment, or keeps recurring, a doctor may prescribe an oral antifungal to attack the infection systemically.
Preventing It From Coming Back
Jock itch is notorious for recurring, but a few consistent habits make a big difference:
- Dry your groin thoroughly after every shower or workout before getting dressed. A separate towel for the groin area helps avoid spreading fungi from the feet.
- Wear loose-fitting cotton underwear. Synthetic fabrics trap heat and moisture. Switch to breathable materials, especially in warm weather.
- Wash workout clothes, underwear, socks, and towels after every single use. Fungi survive on damp fabric between wears.
- Put socks on before underwear if you have or have ever had athlete’s foot. This simple order-of-operations change prevents you from dragging foot fungi up through your groin.
- Wear sandals in locker rooms and public showers to avoid picking up the fungus in the first place.
- Don’t share towels, clothing, or sports equipment. Even if someone else’s infection isn’t visible, they can still shed fungal spores.
Keeping your groin dry is the single most effective prevention strategy. If you tend to sweat heavily, changing underwear midday or using an absorbent body powder can help keep moisture levels low enough that fungi can’t gain a foothold.