Hives

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Introduction

Hives (Urticaria) are red or white itchy bumps that appear on the skin.  Hives result from allergic reactions, environmental factors, and certain medical conditions.  In many cases, hives resolve without medical treatment.  Over-the-counter or prescription medications are the standard treatments for hives.
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Anatomy

Your immune system usually fights germs to keep you healthy.  If you have allergies, your immune system overreacts to ordinary substances that normally are not harmful, such as pollen or certain foods.  The substances that trigger an allergic reaction are called allergens.

When you are exposed to an allergen, your white blood cells produce antibodies.  The antibodies trigger the release of histamine and other chemicals in your blood called mediators.  The mediators can cause hives to appear on the skin.  Deep hives that are located on the face near the eyes or lips are termed angioedema.
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Causes

Hives can be caused by exposure to allergens, such as foods, animal dander, medications, latex, pollen, and insect bites.  Environmental factors, including sun exposure, hot or cold temperature, water, excessive perspiration, emotional stress, exercise, or skin pressure, can cause hives.  Infections, thyroid disorders, blood transfusions, lupus, cancer, hepatitis, and the common cold are examples of medical conditions that can cause hives.
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Symptoms

Hives are red or white welts (wheals) that appear on the skin.  Deeper welts on the face are termed angioedema.  You may have one welt or a group of welts.  The welts may itch, burn, or sting.

The welts may come and go.  Hives can last as long as a day or weeks.  Chronic hives last more than six weeks, and in some cases for months or years.
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Diagnosis

Your doctor can diagnose hives by reviewing your medical history and examining your skin.  An allergist can conduct a skin test or blood test to identify the substances that cause your allergic reactions.
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Treatment

In many cases, hives go away without treatment.  Over-the-counter or prescription antihistamine medication is commonly recommended.  Corticosteroid medications may be prescribed for severe hives. The hereditary type of hives is treated with androgen medications.
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Prevention

You should avoid the allergens or triggers that cause your hives.  It can be helpful to wear loose-fitting cotton clothing.  A cool wet compress or bath with baking soda and finely ground oatmeal can help ease symptoms.
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Am I at Risk

You may be at risk for hives if you have:
• had hives before.
• experienced allergic reactions.
• a medical condition that can cause hives.
• family members that get hives.
• been exposed to allergens or triggers that cause your hives.

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Complications

A severe case of hives may require emergency medical treatment.  You should go to the emergency department of a hospital if you experience difficulty breathing or a swollen throat or swollen airway.  Your doctor may recommend that you carry an emergency shot of adrenaline (epinephrine) or steroids.
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This information is intended for educational and informational purposes only. It should not be used in place of an individual consultation or examination or replace the advice of your health care professional and should not be relied upon to determine diagnosis or course of treatment.

The iHealthSpot patient education library was written collaboratively by the iHealthSpot editorial team which includes Senior Medical Authors Dr. Mary Car-Blanchard, OTD/OTR/L and Valerie K. Clark, and the following editorial advisors: Steve Meadows, MD, Ernie F. Soto, DDS, Ronald J. Glatzer, MD, Jonathan Rosenberg, MD, Christopher M. Nolte, MD, David Applebaum, MD, Jonathan M. Tarrash, MD, and Paula Soto, RN/BSN. This content complies with the HONcode standard for trustworthy health information. The library commenced development on September 1, 2005 with the latest update/addition on February 16, 2022. For information on iHealthSpot’s other services including medical website design, visit www.iHealthSpot.com.