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 on their clothes at waist level. Over time, the body can develop allergies to these substances.
Contact dermatitis is rarely serious. But it is often very itchy.
Psoriasis. There are two types of genital psoriasis: inverse and penile. Inverse psoriasis causes bright red patches and may be itchy. Penile psoriasis causes pale red, scaling patches and does not itch or burn.
Sexually transmitted infections (STIs). Sores, blisters, or ulcers, especially in the groin or genital area, may be the first symptom of several STIs. If you have a rash or growths in the groin or genital area, do not have sexual contact or activity until you have been evaluated by your health professional. This will reduce the risk of spreading a possible infection to your partner. Your sex partner may also need to be evaluated and treated.