Hives, also called urticaria, is a common skin condition in which swollen, pale red bumps, also known as welts or wheals, suddenly break out on the skin. Hives cause itching, stinging or burning and may appear anywhere on the body. Hives are most often an allergic reaction, but sometimes the allergen precipitating the adverse reaction is unknown. Hives is never a contagious condition.
A hive may vary in size from a small dot to an area as wide as eight inches across and, in some cases, hives may combine to form larger areas known as plaques. Usually, hives last for a few hours, to up to a day before fading and disappearing. Very rarely, hives continue to be troublesome for months, in which case the condition is called chronic hives. In severe outbreaks, hives may appear on the tongue or in the throat and interfere with breathing, causing life-threatening complications. If this occurs, medical attention should be sought immediately.
Causes of Hives
Certain substances may cause skin reactions when certain cells release histamine and other chemicals into the bloodstream. Common allergens known to cause hives include:
- Animal dander, particularly cat dander
- Insect bites or stings
- Food allergies
- Intense stress reactions
- Extreme temperature changes
- Excessive perspiration
Foods that commonly cause hives may include: nuts, especially peanuts, shellfish, soy products, gluten, chocolate, strawberries, milk products, spices, and eggs. Medications that commonly cause allergic reactions of this type include aspirin, penicillin and other antibiotics, and sulfa.
Risk Factors for Hives
Individuals with allergies are more likely to develop hives, as are people with a family history of the disorder. Patients with some autoimmune conditions, such as lupus, or certain thyroid disorders, are more prone to hives than people without these diseases.
Treatment for Hives
Usually hives, though uncomfortable, is a harmless condition that will resolve on its own. The following treatments may be helpful in alleviating symptoms:
- Wearing soft, loose clothing
- Bathing in lukewarm water, particularly with an oatmeal solution
- Taking over-the-counter antihistamines
- Applying Calamine lotion to the site
- Avoiding allergens that may be responsible
Avoiding the allergen that has provoked the reaction is, of course, a good idea, but in many cases the substance or material may remain obscure. If hives are severe, oral antihistamines or oral corticosteroids may be prescribed as treatment. In extreme instances, when the face, tongue or throat swell, or when swallowing or breathing is affected, hives become life-threatening. In such cases, immediate emergency treatment is required in the form of an injection of epinephrine. Patients prone to serious allergic reactions with hives are usually prescribed an EpiPen® auto-injector to carry with them at all times for such contingencies.
- National Institutes of Health
- Centers for Disease Control and Prevention
- Eunice Kennedy Shriver National Institute of Child Health and Human Development
- U.S. Department of Health & Human Services
- U.S. National Library of Medicine
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