Jock itch (tinea cruris) is a fungal infection that affects the skin of your genitals, inner thighs and buttocks. Jock itch causes an itchy, red, often ring-shaped rash in these warm, moist areas of your body.
Jock itch gets its name because it is common in people who sweat a lot, as do athletes. It also is more likely to occur in people who are overweight.
Although often uncomfortable and bothersome, jock itch usually isn't serious. Keeping your groin area clean and dry and applying topical antifungal medications usually are sufficient to treat jock itch.
Jock itch usually begins with a reddened area of skin that spreads out from the crease in the groin in a half-moon shape onto the upper thigh. The border of the rash may consist of a line of small, raised blisters. The rash often itches or burns, and the skin may be flaky or scaly.
Jock itch is caused by a type of fungus that can be spread from person to person or from shared use of contaminated towels or clothing. Jock itch is often caused by the same fungus that results in athlete's foot. It's common for the infection to spread from the feet to the groin, as the fungus can travel on your hands or on a towel.
The organisms that cause jock itch thrive in damp, close environments. You're at greater risk of jock itch if you:
- Are a man
- Are a teen or young adult
- Wear tight underwear
- Are overweight
- Sweat heavily
- Have a weakened immune system
- Have diabetes