Urticaria or hives are transient extremely itchy welts that rapidly develop on the skin as an allergic reaction to specific triggers. They usually appear as round or oval smooth elevated red spots. Sometimes these are small and resemble bug bites. Other times, large circular patches merge together forming polycyclic geographic shapes. There is almost always associated intense itching or burning. Hives can appear anywhere on the skin surface and often spread throughout the trunk and extremities, migrating rapidly over hours. There can be severe swelling, especially with deep involvement on the lips and tongue (known as angioedema) or hands and feet.
Most cases of urticaria are acute and subside over a few weeks. Common triggers for acute urticaria include allergic reactions to foods (esp. shellfish, nuts, chocolate, strawberries, tomatoes, onions), food additives or colorings, bee stings, medicines (esp. penicillins, aspirin, sulfa) or as a reaction to internal infections (esp. ear, sinus, tooth or bladder infections). Other infections associated with hives include skin or nail fungus, viral hepatitis and gastrointestinal parasites.
Some cases of hives persist and recur over months to years. These forms of urticaria can be triggered as an allergic reaction to foods, food additives, inhaled airborne allergens (pollens, molds, dust), chronic internal infections or induced as an allergic reaction to physical forces (cold, pressure, sunlight). Chronic urticaria is best evaluated by allergy specialists who perform prick skin tests to look for allergic responses to specific substances.
All forms of urticaria can be treated with various antihistamine medications. Usually a long-acting non-sedating antihistamine is taken in the morning, and then additional short-acting sedating antihistamine is taken as needed during the course of the day for any breakthrough hives. Cortisone shots or pills can also be given for quick short-term relief. Rarely, the allergic reaction becomes so intense that breathing, swallowing or blood pressure are affected. This is a medical emergency that requires immediate treatment in an emergency room with epinephrine (adrenalin).
Hives can recur if you are exposed to the specific offending trigger. For instance, some people will get hives consistently after eating strawberries or with each episode of sinus infection. Attention should be directed toward eliminating the offending trigger and treating the hives with appropriate medicines.
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