Hives are red, itchy welts or swellings on the skin that often come in clusters. They can appear anywhere on the body, cropping up either in one small area or covering large patches of skin. They most often occur as part of an allergic reaction. No one lesion lasts more than 24 hours, but new ones may continue to appear until the condition resolves.
Hives are often caused by a hypersensitivity to:
•Foods (commonly eggs, shellfish, nuts, berries, dyes, or other additives)
•Drugs (any drug can touch off an allergic reaction, although allergies to penicillin, sulfa, and aspirin are especially common)
•Pollens and plants (nettles, poison ivy, poison oak, and so on)
•Insect bites or stings
•Exposure to heat, cold, or sunshine. Other potential triggers include physical exertion or exercise, stress, illness, chemicals, cosmetics, textiles, and pressure from materials rubbing against the skin.
Hives usually appear suddenly and go away on their own in a matter of days, hours, or even minutes.She can take oral anti-histamines and apply Calamine lotion to the areas affected.
Eliminating foods or other triggers that cause you to break out is the key to preventing hives. If you don't know what causes your hives, keep a diary of what you eat as well as what you do each day and what medications and other products you use. Allergy testing can also be helpful.
After an outbreak of hives has gone away, avoid wearing tight-fitting clothing and stay away from hot baths or showers for a while. Both can cause the hives to return.
If you have hives that linger for six weeks or more, ask your primary care doctor for advice. He or she may refer you to a specialist such as an allergist or immunologist. They can do skin or blood tests to help determine what foods or other substances trigger your hives.