Jock itch, also known as tinea cruris, is a fungal infection of the skin in the groin and upper thighs. The fungus that most commonly causes jock itch is called Trichophyton rubrum. Trichophyton rubrum also causes fungal infections of the toes and body. Lesions caused by jock itch can extend from the crease between the inner thigh and pelvis, over the adjacent upper inner thigh, and into the anal area.

Jock itch differs from genital herpes in that it usually doesn't develop on the scrotum or penis. It tends to spread in the inner thigh area instead. However, a jock itch rash may also affect the genitals and areas around the anus, rectum, or vagina. The skin may crack, scale and be painful, but it usually won't present open lesions like it would with genital herpes. Genital herpes doesn't cause long-term infections. Healthy skin returns after 3 weeks, although slight change in skin color may result.

Causes

The fungus that most commonly causes jock itch is called Trichophyton rubrum. It also causes fungal infections of the toes and body. Under the microscope, this fungus looks like translucent, branching, rod-shaped filaments or hyphae. The width of the hyphae is uniform throughout which helps distinguish it from hair, which tapers at the end. Some hyphae appear to have bubbles within their walls, also distinguishing them from hair. Under most conditions these fungi inhabit only the dead skin cells of the epidermis.

Jock itch is caused by the same fungus that causes ringworm (tinea cruris). Jock itch is much more common in men than in women and develops most frequently in warm weather. The infection begins in the skinfolds of the genital area and can spread to the buttocks, upper inner thighs, armpits and underneath the breasts. Usually the scrotum is not involved (unlike in yeast infection). Anyone can get jock itch. Jock itch named because it is usually athletes who get it, but it can affect anyone who tend to be overweight or sweat a lot.

Symptoms

There are several different jock itch symptoms that will let you know if you have it. Do you notice a circular, raised, red rash around your groin? Have you been experiencing a lot of itching? Does it seem like the more you scratch, the more you itch? Have you had any flaking or peeling of your skin in the groin area? All of these are classic symptoms.

A circular, red, raised rash with elevated edges. Itching and redness in your groin, including your genitals, inner thighs, buttocks and anal area. Flaking, peeling or cracking skin in your groin. Abnormally dark or light skin. You may have other fungal skin rashes such as athlete's foot or ringworm on other body parts.

Treatment

Severe infections, frequently recurring infections, or infections lasting longer than two weeks may require further treatment by your doctor. Stronger prescription medications, such as those containing ketoconazole or terbinafine, or oral antifungals may be needed. Antibiotics may be needed to treat bacterial infections that occur in addition to the fungus (for example, from scratching the area).

Side effects from oral medications include gastrointestinal upset, rash and abnormal liver function. Taking other medications, such as antacid therapies for ulcer disease or gastroesophageal reflux disease (GERD), may interfere with the absorption of these drugs. Oral medications for fungal infection may alter the effectiveness of warfarin, an anticoagulant drug that decreases the clotting ability of your blood.