Autoimmune Urticaria

Abstract

Urticaria persisting for longer than 6 weeks is defined as chronic. Rarely is this the result of allergy to an external food or inhalant allergen, although patients and most health professionals still make this assumption. In contrast, it is now established that approximately 50% of cases are caused by autoimmune IgG antibodies to the IgE receptor or IgE on mast cells and basophils. Clinically, this is detected by the autologous serum skin test or a recently developed in vitro assay. Antihistamines often at high doses or in combination are first-line therapy, but recalcitrant cases often require immune modulator therapy such as cyclosporin or methotrexate.