Abstract： Cholinergic urticaria (CU) is characterized by a number of small,short-lasting hives that appear after body core temperature increases,usually,following exercise or bathing.The exact pathogenesis of CU is unclear.Besides acetylcholine,various pathogenetic mechanisms have been postulated to be involved in the development of CU,including sweat allergy,superficial obstruction of the acrosyringium by keratotic plugs,acquired general hypohidrosis,et al.It is suggested that CU can be categorized into four subtypes:CU with poral occlusion,CU with acquired generalized hypohidrosis,CU with sweat allergy,and idiopathic CU.