Chronic urticaria and autoimmunity.

Chronic urticaria is defined as hives, typically occurring daily, for greater than 6 weeks duration. Chronic idiopathic urticaria, which has no discernable external cause, comprises the majority of cases of chronic urticaria. Over half of all cases of chronic idiopathic urticaria are thought to occur by an autoimmune mechanism, primarily autoantibodies against the high affinity immunoglobulin E (IgE) receptor (FcεRI). Chronic urticaria is hypothesized to occur because of a predilection in the patient to develop reactions to self. Supporting this hypothesis, a strong association has been found between chronic urticaria and additional autoimmune diseases, such as thyroid disease, rheumatoid arthritis, systemic lupus erythematosus, Sjögren's syndrome, celiac disease and type 1 diabetes, among others. Herein, we review the associations between chronic urticaria, thyroid disease, and other autoimmune disorders, as well as the implications that these correlations hold for therapeutic intervention in chronic urticaria.