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Chronic urticaria: Clinical manifestations, diagnosis, pathogenesis, and natural history

Sarbjit Saini, MD
Section Editors
Bruce S Bochner, MD
Jeffrey Callen, MD, FACP, FAAD
Deputy Editor
Anna M Feldweg, MD


Chronic urticaria (CU) is defined by the presence of recurrent urticaria (hives), with or without angioedema, for a period of six weeks or longer [1]. As many as 50 percent of patients with CU have accompanying episodes of angioedema [2]. No external allergic cause or contributing disease process can be identified in 80 to 90 percent of adults and children with CU [3-5]. There are several theories regarding the pathogenesis of chronic idiopathic urticaria (CIU), none of which have been conclusively established. CU is a self-limited disorder in most patients, although the average duration of disease is two to five years.

The clinical manifestations, epidemiology, diagnosis, theories of pathogenesis, and natural history of CU will be reviewed here. The management of CU is discussed separately. (See "Chronic urticaria: Standard management and patient education" and "Chronic urticaria: Treatment of refractory symptoms".)


In this review, the term "chronic urticaria" (CU) refers to patients with isolated chronic idiopathic urticaria (CIU), as well as those with both urticaria and angioedema. There are several closely related terms that are used in the CU literature.

Chronic idiopathic urticaria and chronic spontaneous urticaria — The terms "chronic urticaria" (CU), "chronic idiopathic urticaria" (CIU), and "chronic spontaneous urticaria" (CSU) are used interchangeably in this review. CU is the most general term and is used less in the literature over time because it is nonspecific and would often be used to describe patients with a mixture of CIU and physical urticaria (ie, hives triggered by physical stimuli, such as heat, cold, pressure applied to the skin, exercise, water, vibration, and sunlight). Physical urticaria is also called "inducible urticaria." Physical urticaria syndromes are discussed separately. (See "Physical urticarias".)

The term CSU is increasingly used instead of CIU or CU. This term refers to CU in which appearance of lesions is not triggered by consistent or identifiable factors, and it specifically excludes the physical urticaria syndromes or other inducible forms of urticaria. We prefer this term over the others, although it is not as familiar to nonspecialists, so we continue to use the generic term CU.

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Literature review current through: Oct 2017. | This topic last updated: Jun 29, 2017.
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