This study aimed to characterize the association between chronic urticaria (CU), autoimmune diseases, and autoimmune/inflammatory serologic markers. Patients given a diagnosis of CU by either allergy or dermatology specialists during 17 years were included (N = 12,778). Information on diagnosis of major, well-defined autoimmune diseases, and autoimmunityand inflammatory-related serologic markers was collected. Similar data were collected for a control group of patients without CU who visited dermatologists, family physicians, or allergy specialists (N = 10,714). Having CU was found to be associated with an increased odds ratio for hypothyroidism, hyperthyroidism, and antithyroid antibodies. Female patients with CU had a significantly higher incidence of rheumatoid arthritis, Sjögren syndrome, celiac disease, type I diabetes mellitus, and systemic lupus erythematosus, mostly diagnosed during the ten years after diagnosis of CU. High mean platelet volume, positive rheumatoid factor, and antinuclear antibodies were all significantly more prevalent in patients with CU. The authors concluded that CU and major autoimmune diseases are strongly associated and that a common pathogenic mechanism is implied by the high prevalence of autoantibodies and the existence of a chronic inflammatory process expressed by the high mean platelet volume. J Allergy Clin Immunol. 2012 Feb 13. PMID: 22336078
