Doctors use the term rash to describe a change in the color or texture of the skin, according to MedlinePlus. The appearance of a rash varies, depending on the cause, and ranges from small localized areas of redness to expanded areas of raised, itchy hives. Rashes can occur in any part of the body, but rashes in the genital region--the skin surrounding the external sex organs--can be particularly alarming.
Allergic Skin Condition
Dermatitis, also known as eczema, is a general term used to describe any skin condition that causes inflammation in the upper layers of the skin resulting in itching, swelling and blisters. Dermatitis occurs when the skin becomes irritated. A common type of dermatitis, known as contact dermatitis, occurs when an allergen comes in contact with the skin. Common causes of contact dermatitis resulting in a rash in the genital area include creams, ointments, soaps and detergents. The rash of contact dermatitis usually feels itchy and may lead to the formation of blisters.
Chronic Skin Disease
Psoriasis, a chronic skin disease, occurs when the immune cells in the body send out faulty signals that speed up the growth cycle of skin cells, as described by the National Psoriasis Foundation. Five different types of psoriasis exist; it can affect any part of the body. The most common form of psoriasis found in the genital region is inverse psoriasis, which causes smooth, dry and red skin lesions. Psoriasis rash in the genital area may feel itchy and result in additional irritation when scratched.
Scabies describes a parasitic infection caused by a microscopic mite. The mites, which transmit through close human to human contact, burrow under the skin and lay their eggs. The eggs release toxins causing an itchy rash that may appear as little hive-like bumps, red bites or small pimples. Because the mites prefer warm areas, they migrate to the areas where clothing fits tight such as the genital area. Anyone can contract scabies, which causes approximately 300 million new cases worldwide each year, according to the American Academy of Dermatology.
Sexually transmitted disease describes a group of diseases transmitted from one person to another through sexual contact. Many types of sexually transmitted diseases cause a rash in the genital area. Human papillomavirus causes a rash in the genital area known as genital warts. More than 40 strains of this virus exist, some of which can lead to cervical cancer, according to 2009 information from the Centers for Disease Control and Prevention.
Syphilis, caused by the bacterium Treponema pallidum, can begin with the appearance of small, firm, red, painless sores in the genital area. This primary stage can last from 10 to 90 days, according to the Centers for Disease Control and Prevention. If left untreated, these sores develop into a non-itchy skin rash that can spread to other areas of the body, a characteristic of the secondary stage. Late stage syphilis may damage internal organs such as the brain, eyes, heart or liver.