Chronic urticaria is characterized by hives and/or angioedema that According to the UCT, 2 of 26 patients (7.7%) were considered to occurs for more than 6 weeks at a time.1 Although the use of high doses of second-generation histamine1 antihistamines has recently been proposed as a treatment for this condition, biological therapy against IgE has also emerged as a new alternative for the treatment of chronic spontaneous urticaria.2e6 This study assessed the effectiveness of omalizumab to treat spontaneous or inducible urticaria in the Mexican population. The ethics and research committees of the Hospital Regional “Lic. Adolfo López Mateos,” Instituto de Seguridad y Servicio Sociales de los Trabajadores del Estado approved our study, and each patient provided written informed consent to participate. When building our cohort, we included patients 18 years or older who had inducible or spontaneous chronic urticaria and those who had a refractory response to antihistamines at a standard dose after 2 weeks, as defined by a Urticaria Activity Score 7 (UAS-7) score of 16 points or more. We excluded all patients with a history of asthma or allergic rhinitis, anaphylactic reactions or hypersensitivity to omalizumab, neoplasms, greater than 10% weight loss in the 6-month period before the study, and autoimmune disease, women who were pregnant or breastfeeding, and patients using systemic or topical corticosteroids. Consecutive patients were recruited by nonprobability sampling from March 1, 2014, through February 29, 2015. All the patients in our study were initially treated with 5 mg/d of levocetirizine for 2 weeks to control urticaria (157 patients). The 82 patients who responded to the treatment were excluded. The 76 patients who continued to have chronic urticaria with a UAS-7 score greater than 16 points went to a second phase of treatment with 20 mg/d of levocetirizine (4 times the common dose) for 4 weeks. Patients who achieved control of urticaria with this dose (50 patients) did not participate in the final stage. Patients who did not achieve control or had inadequate control of their urticaria (26 patients) continued to the third stage in which omalizumab was administered subcutaneously at a set dosage of 300 mg every 4 weeks. The clinical follow-up was performed monthly using the UAS-7 and Urticaria Control Test (UCT).7 Slightly more than 70% of the patients had spontaneous chronic urticaria, and almost one-third had inducible urticaria (Table 1). Patients with chronic urticaria who were being treated with omalizumab had a baseline median UAS-7 score of 32 points, which became significantly lower after the first month (P < .001) and remained so until the sixth month of treatment. When the study was completed, no patients had a complete response, and 26 patients manifested a UAS-7 score of 6 or less. Patient control of urticaria, as measured by the UCT, revealed a significant increase in the median score, ranging from 6 to 13 points (P < .001). This improvement was consistent for 4 weeks after the first dose of omalizumab, and notably, therewas progress until the sixthmonth.