Abstract: The etiology of chronic idiopathic urticaria (CIU) remains unclear.Recent studies have found that autoimmune mechanisms are involved in the development of CIU in most cases.Several autoantibodies have been found to be associated with CIU.In these autoantibodies,the anti-FcεRI and anti-IgE antibodies appear to play key roles in the pathogenesis of CIU.B lymphocyte stimulator may take part in the production of autoantibodies.Moreover,the frequency of HLA-DRB 1*04 allele is higher in patients with CIU,suggesting a genetic background underlying autoimmune CIU.