Unresponsiveness to Omalizumab in Chronic Spontaneous Urticaria

Purpose of the Review Omalizumab has become the mainstay of the treatment of severe CSU, but a subset of patients seems completely unresponsive to the drug. This review tried to understand the reasons for this different behavior. Recent Findings Growing evidence shows that IgE-mediated autoimmunity to an array of autoallergens is common in CSU, while IgG-mediated autoimmunity to IgE or to the highaffinity IgE receptor, which has been known for many years, seems to be involved in a minority of patients. This may explain the different responsiveness to anti-IgE therapy. Summary CSU is probably an autoimmune disease in most cases. Patients with an IgEmediated disease (autoallergy) seem those who respond to omalizumab, whereas those with an IgG-mediated autoimmune disease appear to respond slowly or are unresponsive to the drug and are candidates to the immunosuppressive treatments, like cyclosporine.