What are hives? — Hives are raised, red patches of skin that are usually very itchy (picture 1). They can happen because of an allergy or other causes. In most cases, hives come and go within a few hours. But they can show up again and again in some people.
Some people who get hives also get a condition called "angioedema." Angioedema is puffiness or swelling. It usually happens in the face, eyelids, ears, mouth, hands, feet, or genitals.
Some people who get hives or angioedema are having a dangerous allergic reaction. See a doctor or nurse right away if you suddenly get hives or get puffy and also have any of these symptoms:
Tightness in the throat
Nausea and vomiting
Cramps or stomach pain
Why did I get hives? — If you just got hives for the first time, you might have a new allergy to something. People can get hives because of allergies to:
Medicines, such as antibiotics or aspirin
Foods, such as eggs, nuts, fish, or shellfish
Something they touched, such as a plant, animal saliva, or latex
If your hives are caused by an allergy, you will need to avoid whatever you are allergic to.
Hives can also be caused by:
Having cold air or water on the skin
Having something press or vibrate against the skin
Changes in body temperature (such as when you cool down after a hot shower or a work out)
If you have had hives on most days for more than 6 weeks, you may have "chronic hives." Chronic hives are not caused by an allergy. In most cases, doctors do not know what causes chronic hives.
If you have chronic hives, you will probably need to take medicines every day to control them. Luckily, chronic hives do usually go away with time.
How are hives treated? — You might not need treatment. Hives usually go away in a few days or weeks, even if you do not get treated. If you have hives for the first time, talk to your doctor or nurse about whether or not you need treatment. If you do, the first step will be to figure out if anything triggered the hives. If so, you will need to avoid that trigger.
To relieve itching, you can take medicines called antihistamines. These are the same medicines people usually take for allergies.
If you have severe hives or your hives will not go away, your doctor or nurse might suggest that you take medicines called steroids for a short time. Steroids work well to relieve itching and reduce swelling. But you should not take them for long, because they can cause serious side effects. These are not the same as the steroids some athletes take illegally.
All topics are updated as new evidence becomes available and our peer review process is complete.
This topic retrieved from UpToDate on: Mar 30, 2020.
Topic 15456 Version 7.0
Release: 28.2.2 - C28.105
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