Update on Antihistamine Treatment for Chronic Urticaria in Children

Urticaria is a heterogeneous group of diseases, which may have different causes and mechanisms but share similar clinical features. It is clinically defined by the presence of wheals and/or angioedema. The diagnosis of urticaria is based on the evaluation of clinical manifestations. Urticaria is conventionally classified as acute or chronic. Chronic urticaria (CU) has been defined as daily or nearly daily occurrence of wheals and/or angioedema lasting longer than 6 weeks. Very little is known of the epidemiology of urticaria in infants and children, and still less is known of the prevalence of CU. The prevalence of CU in children is reported to vary between 0.1 and 0.3 %. The natural history of CU in children tends toward spontaneous resolution: approximately 25 % of patients go into remission within 3 years. Many etiological factors have been associated with CU, but most cases remain idiopathic despite exhaustive investigations. Among the non-idiopathic CU cases, the most common etiologies are autoimmune origin, followed by physical triggers. Food allergy and intolerance, as well as infections, are other less frequent possible causes. However, well-controlled studies to support the different etiologies and/or associations are lacking. The management of childhood CU includes identification and elimination of the triggering factors and symptomatic pharmacological treatment when symptoms appear. The first-line symptomatic therapy is second-generation H1-antihistamines, with dose adjustment for pediatric use. Only a few H1-antihistamines have been investigated for safety in children: cetirizine, levocetirizine, loratadine, fexofenadine, desloratadine, and rupatadine; of these, cetirizine and levocetirizine are the ones that have been most thoroughly investigated for long-term safety and efficacy in children ranging from 6 months to 12 years of age. Corticosteroids and other immunosuppressive drugs (e.g., cyclosporine A, dapsone, and omalizumab) should be restricted to very refractory CU cases and used only for a very short period.