Most people suffer from an itchy, reddened or scaly skin condition at some time in their life, but rarely are skin rashes cause for concern. The term "rash" is broadly defined as a skin disorder that results in a change in skin appearance, either by color or texture. A majority of rashes are minor and will correct themselves in a few days, even if the cause is not determined. A few rashes, however, result from a chronic skin condition or may appear as a symptom of another disorder.
Redness, with or without itchiness, is present in the most common form of rash and may be a symptom of an allergy to a household substance, plant or animal. Many rashes that feature itchy and scaly patches are the result of eczema, a condition seen in people of all ages. Also known as dermatitis, these mild eczema outbreaks often resolve themselves, especially in young children. Severe rashes need medical attention to prevent the infection of blisters or boils or to prevent the spread of infection.
Eczema rashes most often appear on the inside of the elbows or knees or on the lower portion of the legs. They may also appear on the sides and back of the neck; in some sufferers, the rash may spread to the face and ears. If the rash lasts more than a couple of days or if it returns, it may be chronic dermatitis. Rashes caused by other conditions may be located on different parts of the body.
If a rash is not eczema, it may be a symptom of another disorder. A virus that attacks the immune system, such as shingles, HIV or chicken pox, can cause a distinctive and sometimes severe rash. Fungus, contracted by contact with an infected person or an animal, may result in athlete's foot or ringworm rashes. Other rash inducers are stress, an adverse reaction to a drug, excess body heat, sweating or insect bites.
A doctor will visually inspect the rash and may order a skin-patch test if he suspects the trigger is a household or environmental substance. An allergist performs the patch test by applying tiny amount of known allergens to different areas of the skin and recording the reaction to each test spot. A physician may also order a skin biopsy if he feels the rash is caused by an underlying disorder, such as cancer or infection.
The first line of defense in treating a rash is to alleviate any pain, itching and the further spread of the rash. The doctor may prescribe an antibacterial, antifungal or a steroid-based cream to stop the spread of a rash. In addition, oral antibiotics or steroids may be in order if the rash is severe and spreading through the bloodstream. For mild rashes, many over-the-counter products are available that contain tar, peroxide, salicylic acid and nonprescription-strength cortisone ointments.
A medical professional should inspect any rash that does not go away within a few days or worsens. If infection, elevated heat in the rash area or the sudden spread of a rash that was receding occurs, seek medical attention.