Hives are small, itchy, red swollen areas on the skin. The swelling occurs alone or in groups. Most hives tend to fade within a few hours to 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.
Things that may cause hives are:
- Food allergies or reactions, most commonly:
- Fish or shellfish
- Wheat or soy
- Insect bites or stings
- Pressure, cold, heat, or sun
- Certain health problems, such as:
Things that may raise the risk of hives are:
- Being exposed to an allergen—something that causes an allergic reaction
- Being exposed to something that triggered hives in the past
Symptoms of hives can vary from mild to severe. They may include:
- Itchiness, redness, and swelling
- Excessive swelling of the eyelids, lips, or genitals
- Burning or stinging
- Problems breathing or swallowing
The doctor will ask about symptoms and past health. A physical exam will be done. The person may be referred to a doctor who treats skin disorders or allergies.
Tests may be done, such as:
The goal is to find and avoid the cause of hives.
Medicines may help to ease symptoms and manage the cause. They may be applied to the skin or taken as a pill. They may include:
- Leukotriene antagonists
- Anti-inflammatory medicines
- Medicines to treat the immune system
Other treatments may include:
- UV light therapy—for long term hives that do not respond to other treatment
- Epinephrine (adrenalin) injections—if swelling affects the airways
Sometimes hives are a sign of anaphylaxis. This is a severe reaction that can be life-threatening. If swelling affects breathing, emergency care is needed.
The best way to prevent hives is to avoid allergens that caused hives in the past.
- Acute urticaria. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/acute-urticaria.
- Allergic skin conditions. American Academy of Allergy, Asthma & Immunology website. Available at: http://www.aaaai.org/conditions-and-treatments/library/at-a-glance/allergic-skin-conditions.
- Chronic urticaria. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/chronic-urticaria.
- Hives: overview. American Academy of Dermatology website. Available at: https://www.aad.org/public/diseases/a-z/hives-overview.
- Saini SS, Kaplan AP. Chronic spontaneous urticaria: the devil's itch. J Allergy Clin Immunol Pract. 2018;6(4):1097-1106.
- April Scott, NP
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