Hives (urticaria) - close-up

Hives develop when histamine is released into the small blood vessels (capillaries). The capillaries dilate which causes a welt, and fluid oozes into the surrounding tissue, causing swelling. Histamine also causes intense itching.
Review Date: 04/15/2009
Reviewed By: Kevin Berman, MD, PhD, Associate, Atlanta Center for Dermatologic
Disease, Atlanta, GA. Review provided by VeriMed Healthcare
Network.












