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What are hives?
Hives (urticaria) are bumps that you get on your skin. They are sometimes referred to as welts. It is a common condition that you can get at any age. Hives can occur anywhere on your body in a variety of shapes and sizes. You can get hives as an allergic reaction or from stress. They can be red, itchy, and swollen.
Hives are swelling on the surface of your skin. Hives differ from a similar condition called angioedema, which is swelling under skin. You can have these conditions at the same time or separate.
Symptoms of hives
Common symptoms are itching, redness, and swelling. Symptoms can appear right after an allergic exposure or later on, and can occur in any order. Hives bumps also are known as welts, or wheals. The bumps have clear edges and can blend to create patches of raised skin. You can get hives in a small, focused spot or in a large area. Another sign of hives is if you press the red bump and the middle part turns white (known as blanching).
What causes hives?
Most people get hives from an allergic reaction. Your body responds to allergies by releasing chemicals into your blood. These chemicals, such as histamine, trigger the bumps and swelling known as hives.
Common allergies that produce hives include:
- poisonous plants
- insect bites
- various foods and preservatives
- animal dander
- materials, like wool or latex.
You also can get hives from:
- hay fever
- infection or illness
- sweating too much
- tight clothing
- quick change in body temperature
- extreme weather, such as too cold or too hot.
Vasculitis is a rare condition where your blood vessels inflame. It can cause hives that are more painful.
How are hives diagnosed?
Your doctor can diagnose hives by looking at your skin. They also might want to perform blood, skin, or urine tests, such as a skin-prick test or biopsy. These tests can confirm if you had an allergic reaction and what caused it. However, sometimes the cause of hives is unknown.
Can hives be prevented or avoided?
Hives cannot always be prevented. You might not know you are allergic to something, or you met get hives from unplanned stress or elements.
You can help reduce the chance of getting hives if you:
- Avoid food or substances that you (know you) are allergic to.
- Avoid wearing tight clothing for long periods of time.
- Monitor your stress levels.
- Wash your hands regularly.
- Avoid too much sun contact.
- Regulate extreme body and weather temperatures.
- Avoid too much sun contact.
Most cases of hives go away on their own. However, there are things you can do to lessen the effects (itchiness and swelling), such as:
- Avoid scratching the itchy area.
- Take a cool bath or shower (or a hot bath or shower, in cases of cold-induced hives).
- Use a cold cloth or pad.
- Apply an anti-itch cream.
- Wear loose clothing.
- Take an antihistamine, such as Benadryl, to counter the histamine (chemical allergic reaction).
- Avoid alcohol, tobacco, and exercise.
You might need extra treatment if you have a severe case of hives or if the bumps occur in a sensitive area, like the throat, lips, or eyes. Your doctor can give you a shot of epinephrine (adrenaline) or steroids.
Living with hives
Hives typically last for a short time and go away on their own. It is uncommon for hives to leave bruising or scars. Contact your doctor if your hives last for more than 6 weeks. You might have chronic hives and need to see an allergy or dermatology (skin) doctor to manage the condition. He or she may ask you to keep a diary of foods and substances that you’ve been exposed to. This will help determine what you could be allergic to.
Hives typically are harmless, but there are some risks. If your whole body reacts, you might have other problems, like anaphylaxis. This causes swelling in your throat and breathing problems that can be life threatening.
Call 911 or go to the emergency room if you experience:
- shortness of breath or difficulty getting air in your lungs
- swelling in your tongue, throat, or face
Questions to ask your doctor
- How do I know if I have hives versus another skin rash?
- If I get hives once, what is the chance I will get it again?
- Are hives contagious?
Copyright © American Academy of Family Physicians
This information provides a general overview and may not apply to everyone. Talk to your family doctor to find out if this information applies to you and to get more information on this subject.