IGHE and chronic idiopathic urticaria: Pathophysiologically, chronic spontaneous urticaria is a mast cell-mediated disease, and underlying autoimmune mechanisms with mast cell-activating antibodies (autoimmunity type I with IgE autoantibodies against endogenous antigens and autoimmunity type IIb with IgG anti-IgE/FcεRI antibodies) have been identified.