This problem starts as a minor itch near the groin. Soon, it becomes a major itch that drives you up the wall. Closer inspection of the affected area reveals red, oozing and maybe even crusty skin. While this may be a fine time to consult a doctor (as you should for any problem down there), it's not an easy thing to mention, considering how sensitive many people are about their private parts.
Officially known as tinea cruris, jock itch is a common condition caused by fungal growth, friction, heat and humidity. Usually, it starts out in the crease where your legs join your torso. Left unchecked, it can spread to your thighs, buttocks and genitals. In severe cases, untreated jock itch can cause ulcers, open sores, abscesses and even skin infection.
Though this problem usually affects men, women can get jock itch as well, and non-sporty slackers of either gender can get it despite the "jock" tag. It occurs when the skin is moist and warm (for example, when you're sweating after a brisk run), creating an ideal environment for the fungi, which are always present on your skin, to thrive. But it can also spread from person to person through towel- and clothes-sharing.
Call up your doc for a quick consult as soon as you start noticing symptoms, and usually he or she can help you treat jock itch through the use of antifungal sprays and lotions, or with prescribed antifungal pills.