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.
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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: Foods
, most commonly:
InfectionsInsect bites or stingsLatexPressureCold or heatSunlightPollenStressUnderlying medical conditions: Vasculitis (inflammation of the blood vessels)
orhyperthyroidismSome cancers, such as lymphomaViral infections, such as HIV infection, hepatitis, and cytomegalovirus
Factors that may increase your risk of hives include: Exposure to an allergen—something that causes an allergic reactionExposure to an allergen that triggered hives in the past
Symptoms of hives can vary from mild-to-severe: ItchinessRednessSwellingExcessive swelling of the eyelids, lips, or genitalsBurningStinging
Difficulty breathing or swallowing—
Call for emergency services right away
if you are having these symptoms.
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: Blood testsSkin prick testSkin biopsy
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:
Leukotriene antagonists Oral steroid medications for hives resistant to other treatmentsAnti-inflammatory medicationsImmunosuppressant medicationsUltraviolet light therapyPrescription epinephrine (adrenalin) injections for cases when swelling affects the airways
The best way to prevent hives is to avoid the allergen that caused you to get hives in the past.
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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.
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