Rashes in the groin or genital area are usually caused by irritation of the skin from many sources, such as clothes rubbing against the skin. Rashes that occur without other symptoms are usually minor and often go away with home treatment.
A common cause of a rash is contact with a substance that causes irritation or an allergic reaction (contact dermatitis). People who work with soaps, solvents, or detergents might splash these liquids onto their clothes at waist level. Over time, the body can develop allergies to these substances.
Contact dermatitis is rarely serious, but is often very itchy.
Certain diseases may increase your risk of a serious infection. People with diabetes, peripheral arterial disease, or an impaired immune system may require medical treatment at the first signs of infection.
WebMD Medical Reference from Healthwise