Hives are small, itchy, red swollen areas on the skin. The swelling occurs singularly or in clusters. Hives tend to fade after a few hours, but new ones can appear. Most cases go away within a few days. However, some last a few weeks or longer.
Hives are often caused when the body releases a chemical called histamine. Histamine is released during an allergic reaction. Many people, though, get hives without being exposed to something they are allergic to.
While the cause is unknown in some cases, these factors may cause hives:
Factors that may increase your risk of hives include:
Symptoms of hives can vary from mild-to-severe:
You will be asked about your symptoms and medical history. A physical exam will be done. You may need to see a doctor who specializes in skin disorders (dermatologist) or allergies (allergist).
Your bodily fluids and tissues may be tested. This can be done with:
Images may be taken of your bodily structures. This can be done with x-rays.
The best way to treat hives is to find and then avoid the cause.
If the cause can't be found, there are medications to reduce symptoms or treat hives:
American Academy of Allergy, Asthma, and Immunology
American Academy of Dermatology
Canadian Dermatology Association
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Hives. American Academy of Dermatology website. Available at: http://www.aad.org/dermatology-a-to-z/diseases-and-treatments/e---h/hives. Accessed September 22, 2015.
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Urticaria. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed. Updated July 1, 2015. Accessed September 22, 2015.
Last reviewed September 2015 by Marcin Chwistek, MD
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.