Clinical predictive factors of unresponsiveness to omalizumab in patients with chronic spontaneous urticaria.

Chronic spontaneous urticaria (CSU) is an inflammatory disease which is characterized by spontaneous appearance of wheals (hives), angioedema or both for at least six weeks. Approximately 10% of patients suffering from CSU are unresponsive to second-generation H1-antihistamines. For these severe cases, recommendation is a treatment by omalizumab (OMZ) -a humanized anti-IgE monoclonal antibody. However, approximately 20% of patients are still non-responders to OMZ.