Hives are a very itchy rash usually caused by an allergic reaction. Hives look like raised pink spots with pale centers on the skin. The spots range from 1/2 inch to several inches wide (hives often look like mosquito bites). The spots may be different shapes. The spots rapidly and repeatedly change in location, size, and shape. Giant hives are called angioedema.
Widespread hives are an allergic reaction to a food, medicine, viral infection, insect bite, and a host of other substances. Often the cause is not found. Hives found on just one part of the body (localized) are usually due to skin contact with plants, pollen, food, or pet saliva. Localized hives are not caused by drugs, infections, or swallowed foods. Hives are not contagious.
Rarely, hives may also be caused by:
More than 10% of people get hives. Most teens who develop hives have it only once. The hives come and go for 3 or 4 days and then mysteriously disappear.
The best drug for hives is an antihistamine. An antihistamine won't cure the hives, but it will reduce their number and relieve itching.
Benadryl (diphenhydramine), is the most commonly used drug for hives, and is available without a prescription. The main side effect of this drug is drowsiness in some people. Other antihistamines (for example, store brands of any drug for hay fever) will also help. If you are taking Benadryl, take it 3 to 4 times a day until the hives are gone for 12 hours.
Use the drug recommended by your healthcare provider.
For flare-ups of itching, take a cool bath without soap for 10 minutes. Put a cold washcloth or ice cube on itchy areas for 10 minutes. Avoid heat or rubbing.
Avoid anything you think might have caused the hives. For hives triggered by pollen or animal contact, take a cool shower or bath. For localized hives, wash the allergic substance off the skin with soap and water. Localized hives usually disappear in a few hours and don't need Benadryl. Avoid heat or rubbing, which makes hives worse.
Many people wait to take the antihistamine until new hives have appeared. This means you will become itchy again. The purpose of the medicine is to keep you comfortable until the hives go away. Therefore, take the medicine regularly until you are sure the hives are completely gone.
Since hives are not contagious you can be with other people.
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