MedlinePlus Medical Encyclopedia: Hives (urticaria)

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Hives (urticaria) - close-up

Hives (urticaria) are raised, red, itchy welts. The majority of urticaria develop as a result of allergic reactions. Occasionally, they may be associated with autoimmune diseases, infections (parasitosis), drugs, malignancy, or other causes.

Update Date: 4/28/2006

Updated by: Michael Lehrer, M.D., Department of Dermatology, University of Pennsylvania Medical Center, Philadelphia, PA. Review provided by VeriMed Healthcare Network.

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