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Definition
The popular term for a group of spots or red, inflamed skin that is usually a symptom of an underlying condition or disorder. Often temporary, a rash is only rarely a sign of a serious problem.
Description
A rash may occur on only one area of the skin, or it could cover almost all of the body. Also, a rash may or may not be itchy. Depending on how it looks, a rash may be described as:
- blistering (raised oval or round collections of fluid within or beneath the outer layer of skin)
- macular (flat spots)
- nodular (small, firm, knotty rounded mass)
- papular (small solid slightly raised areas)
- pustular (pus-containing skin blister)
Causes and symptoms
There are many theories as to the development of skin rashes, but experts are not completely clear what causes some of them. Generally a skin rash is an intermittent symptom, fading and reappearing. Rashes may accompany a range of disorders and conditions, such as:
- Infectious illness. A rash is symptom of many different kinds of childhood infectious illnesses, including chickenpox and scarlet fever. It may be triggered by other infections, such as Rocky Mountain spotted fever or ringworm.
- Allergic reactions. One of the most common symptoms of an allergic reaction is an itchy rash. Contact dermatitis is a rash that appears after the skin is exposed to an allergen, such as metal, rubber, some cosmetics or lotions, or some types of plants (e.g. poison ivy). Drug reactions are another common allergic cause of rash; in this case, a rash is only one of a variety of possible symptoms, including fever, seizures, nausea and vomiting, diarrhea, heartbeat irregularities, and breathing problems. This rash usually appears soon after the first dose of the course of medicine is taken.
- Autoimmune disorders. Conditions in which the immune system turns on the body itself, such as systemic lupus erythematosus or purpura, often have a characteristic rash.
- Nutritional disorders. For example, scurvy, a disease caused by a lack of Vitamin C, has a rash as one of its symptoms.
- Cancer. A few types of cancer, such as chronic lymphocytic leukemia, can be the underlying cause of a rash.
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Author Info: Carol A. Turkington, The Gale Group Inc., Gale, Detroit, Gale Encyclopedia of Medicine, 2002 |
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·As a Complication
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