Urticaria is a common affliction that can be frustrating to patients b
eset with chronic pruritus and wheals as well as baffling to physician
s who search for the cause and an effective treatment. Even in the abs
ence of clearly identifiable causes, however, the treatment of urticar
ia may be guided by an understanding of the various pathophysiologic m
echanisms involved. Antihistamines, the mainstay of therapy in urticar
ia, have been augmented through the development of nonsedating compoun
ds of high efficacy. Mast cell stabilizers and other inhibitors of urt
icaria mediators may prove effective in selected cases. Optimal therap
eutic outcomes often require trials of various medications guided by t
he clinical response within the limits of acceptable side effects.