International Journal of Asthma, Allergy and Clinical Immunology Official Journal of the Spanish Society of Pediatric Allergy and Clinical Immunology

Chronic idiopathic urticaria (CIU) is characterized by multiple swollen raised areas on the skin that are intensely itchy. These lesions can last less than 24 hours and persist for more than 6 weeks. CIU affects 0.5-1 % of the population and causes a signifi cant decrease in the quality of life. The major advance in our understanding of CIU in recent years has been the discovery that in 30-50 % of patients with CIU the disease is due to an autoimmune process, and therefore is not strictly ‘idiopathic.’ Patients with chronic autoimmune urticaria (CAU) have circulating antibodies against the high affinity receptor FceRI or against IgE. These antibodies are functionally active and therefore they stimulate the release of histamine by basophils and mast cells. The existence of these antibodies has been confi rmed by the use of Western Blot and ELISA. These antibodies can also be identified with the autologous serum skin test due to the ability of serum samples to release histamine from basophils. There is an important correlation between a positive autologous serum skin test and the disease activity. CIU causes an important decline in the quality of life and increases annual direct and indirect health care costs. There are few studies that reveal the presence of CAU in children even though in some series the prevalence of CAU in children ranges from 31 % to 40 %. In developing countries this prevalence is unknown. Patients with CAU are poor responders to antihistamine therapy, and immunosuppressive therapy is warranted. Management of children with CAU in third world countries is very limited due to the unavailability of in vitro testing; the lack of access to specialised centres; and the high cost of medicines. These conditions are a real challenge for the allergist and the dermatologist.