Jock itch, also known as tinea cruris, is a fungal infection of the skin in the groin. The warm, moist environment is the best place for the fungus to grow.

The best way to diagnose tinea cruris is to look for hyphae under the microscope, a KOH test. The skin is scraped with a scalpel or glass slide causing dead skin cells to fall off on a glass slide.

Jock itch is best treated with topical creams or ointments since the fungus only affects the top layer of skin. Lots of the antifungal medications require a prescription, but there are three that can be bought over-the-counter (OTC).

Jock itch is usually less severe other than tinea infections. If it is not treated, though, it can last for weeks or months. Symptoms of jock itch include: a circular, red, raised rash with elevated edges, itching, chafing, or burning in the groin, thigh, or anal area, skin redness in the groin, thigh, or anal area, flaking, peeling, or cracking skin.

The fungus that most commonly causes jock itch is called Trichophyton rubrum. It also cause fungal infections of the toes and body. Under the microscope, the fungus looks like translucent, branching, rod-shaped filaments or hyphae. Therefore, wearing sweaty, wet clothing in the summer season or wearing several layers of clothing in the wintertime causes an increased incidence of jock itch. More often men are prone to this disease than women.