[Argentine guidelines for urticaria and angioedema].

This interdisciplinary paper summarizes the news in the diagnosis and treatment of chronic urticaria (CU), and provides concepts, definitions and evidence-based suggestions for its management. Urticaria occurs in at least 20% of the population at some point in their lives. Acute urticaria (less than 6 weeks' duration), differs from CU in its etiology, but the onset of this disease is always acute. CU may occur as spontaneous (SCU) or induced (ICU). The diagnosis is simple, although a careful evaluation is necessary for differential diagnosis. ICU's diagnosis is mainly clinical, even if provocation tests can be useful. Supplementary studies should be limited and based on the clinical suspicion. Treatment may be divided into three approaches: avoidance, elimination or treatment of the cause, and pharmacological treatment. Recently treatment has been modified with the use of second-generation antihistamines as first-line and increased doses of nonsedating H1 antihistamines, up to 4 times, as second line. Antihistamines are essential to treat CU; however, 40% of patients do not achieve good control despite increased doses and require additional treatment. The most recent evidence indicates a group of drugs to be used as third line in these cases, to improve quality of life and to limit toxicity from frequent or chronic use of systemic steroids. Only 3 drugs are recommended as third line: omalizumab, cyclosporin A or anti-leukotrienes.