The objective of the present study is to demonstrate with an adequate methodology the efficacy and safety of Omalizumab for a new indication that is chronic autoimmune and no autoimmune urticaria. For that purpose, The investigators will perform a Multicenter double- blinded, placebo- controlled, randomized cross-over (2x2) trial. The investigators will include 20 patients including both female and male adults non respondent to antihistamines at supra therapeutic dose. Efficacy will be evaluated through the Urticaria Activity Score 7 (UAS7), Chronic Urticaria Quality of Life validated questionnaire, patients' symptoms card and use of medication. Dropouts in each treatment group will be also evaluated. The investigators will also record leave days because of urticaria and Emergency Department visits, as well as adverse reactions during treatment.