urticaria

views updated

urticaria (nettle rash, hives) (er-ti-kair-iă) n. an itchy rash resulting from the release of histamine by mast cells. Individual swellings (weals) appear rapidly and resolve spontaneously within hours. Angio-oedema occurs when the weals involve the lips, eyes, or tongue, which may swell alarmingly and constitute a medical emergency. acute u. a common and immediate response to such allergens as seafood or strawberries. cholinergic u. a condition in which very small weals are brought on by heat, exercise, or emotion. chronic u. a condition that is not allergic and may persist for years.

More From encyclopedia.com