The autoimmune nature of chronic urticaria

The association between chronic urticaria (CU) and autoimmune disease has been recognized for some time, especially with autoimmune thyroid disease. More recently, functional IgG autoantibodies against FcepsilonRIalpha and less commonly against IgE have been reported in a subset of patients with CU. These patients have been described as having more severe and difficult-to-control urticaria. The autologous serum skin test has been proposed as a surrogate test to define presence of these autoantibodies, although it identifies presence of histamine releasing factor, not necessarily antibody. Basophil histamine release and basophil activation assays using flow cytometry to measure CD63 and, more recently, CD203c expression have been used to identify patients with autoimmune urticaria. New research suggests that in some patients with CU, the activation of the extrinsic coagulation pathway with thrombin generation might play an important role in their CU.