hive

hive A raised, itchy area of skin that is often a sign of an allergic reaction. A hive can be rounded or flat topped but is always elevated above the surrounding skin. It reflects circumscribed edema (local swelling) of the skin. Hives are usually well circumscribed but may be coalescent, and they blanch with pressure. They may last for several minutes, hours, or may persist for days. Approximately 20–25 percent of the population has experienced hives. Treatment is administration of antihistamines. Also known as urticaria and welt.