Second- and third-generation antihistamines in the treatment of urticaria

ABSTRACT: Chronic urticaria is mainly idiopathic in nature and can be difficult to treat. While less responsive to antihistamine therapy than acute urticaria, antihistamines still play a key role in the management of symptomatology. While many of the antihistamines still commonly used to treat urticaria are first generation H₁ antagonists (e.g., diphenhydramine, hydroxyzine), the more recently developed second-generation agents (e.g., loratadine, cetirizine) and their metabolites—the third-generation antihistamines (e.g., fexofenadine, norastemizole, descarboxyloratadine)—possess many of the desirable clinical effects of the first-generation agents with a more tolerable side effect profile. This review discusses the advantages and disadvantages of each of the various second- and third-generation agents available, and presents some of the data showing the differences among these agents in the treatment of chronic urticaria.