When an infection begins in the groin area, pain, itching and embarrassment can ensue. Relief comes from scratching, but scratching the groin, at least in public, is taboo. Figuring out the cause of the infection, then, becomes a high priority as treating it correctly and quickly can resolve the infection and lessen the itch.
Tinea infections are fungal infections of the skin. When they occur in the groin area, it is called "tinea cruris," or more colloquially, "jock itch." The culprit in jock itch infections includes a group of fungi called "dermatophytes." Dermatophytes are microscopic fungi that live in soil, on humans, on objects or even on some animals for long periods of time, which means abundant opportunities exist for coming into contact with the fungi. Dermatophytes enter skin through small tears or lesions. They prefer moist environments, such as showers, pools, saunas and, yes, the groin. Dermatophytes feed on keratin, a protein found in skin, hair and nails. They can be picked up on the feet, where they can take hold and cause athlete's foot or a fungal nail infection. Cross-contamination occurs commonly, so those with athlete's foot often develop jock itch as well. When the fungi take hold, they release an enzyme to break down the keratin so they can absorb it. The enzyme, as well as the metabolic waste produced by the fungi, causes inflammation and the irritation can cause severe itching. Jock itch generally affects the groin area, the upper thighs, and the creases between the buttocks and around the anus, says the Mayo Clinic. It does not generally cause a rash on the penis or scrotum.
Candida is a common, yeast-like fungus that can cause a variety of skin disorders. When it infects the vagina, candidal vulvovaginitis results with symptoms that include itch. The Mayo Clinic website, MayoClinic.com estimates that three out of four women will develop a vaginal yeast infection at some point. The infection can also produce a thick, white vaginal discharge that resembles cottage cheese. Candida can infect men, causing "balanitis." When it does, the infection, and related itch, usually begins on the tip of the penis. Red plaques of irritation work their way down the shaft of the penis to the groin area. Yeast infections are not considered sexually transmitted diseases, because candida occurs normally in humans. When the immune system becomes weakened, or after periods of antibiotic use such as when the body's "helpful" bacteria are decimated, candida albicans can overproduce and cause an infection.
The groin area often becomes moist as a result of small, constant amounts of perspiration released by sweat ducts to the area. Tight clothes, such as jock straps, tight underwear, fabrics that do not allow for airflow, add to the atmosphere that certain fungi and bacteria thrive in. Intertrigo develops when moist areas of skin rub against each other and cause irritation. The irritation causes a red, itchy rash and small tears in skin. Once the tears open, fungi and bacteria can enter the site and infect the region. According to MayoClinic.com, the rash often turns a reddish-brown color and oozing and crusting is common.