Chronic urticaria affects up to 1% of the population. Rarely, chronic urticaria may be refractory to updosing four-fold antihistamine drugs and then can be improved with subcutaneous OMALIZUMAB. OMALIZUMAB is available for chronic urticaria since 2015. It is an IgG1 monoclonal antibody targeting IgE and administrated every 4 weeks which represent a cost of nearly 800€/month excluding nurse fees. Efficacy and good tolerance have already been demonstrated in real-life large cohorts of patients. A 6 months treatment duration is proposed before evaluating the efficacy and discontinuating the treatment in the absence of adequate response. Mean duration of chronic urticaria is 3 to 5 yearss with high standard deviations. Therefore, optimal duration of treatment with OMALIZUMAB is unknown and discontinuation modalities differ between physicians.~The aim of this study is to evaluate the mean duration between initiation and first discontinuation of OMALIZUMAB in patients treated for chronic urticaria and explore the different factors influencing this duration and its outcome.~To accomplish this, the investigators will conduct a restrospective analyse of all patients treated with OMALIZUMAB for chronic urticaria from 2010 to 2020 in the major French hospital reference centers for chronic urticaria management : Paris, Lyon, Grenoble, Lille, Bordeaux, Nantes, Rouen, Saint-Etienne, Montpellier.
Chronic urticaria affects up to 1% of the population. Chronic urticaria refractory to updosing antihistamines can benefit from OMALIZUMAB, which is an anti-IgE IgG1 monoclonal antibody administrated every 4 weeks subcutaneously which represents a cost of nearly 800€/month excluding nurse fees. Efficacy and good tolerance have already been demonstrated in real-life large cohorts of patients. A 6 months treatment duration is proposed before evaluating the efficacy and discontinuating the treatment in the absence of adequate response. Mean duration of chronic urticaria is 3 to 5 years with high standard deviations. Therefore, optimal duration of treatment with OMALIZUMAB is unknown and discontinuation modalities differ between physicians.~The aim of this study is to evaluate the mean duration between initiation and first discontinuation of OMALIZUMAB in patients treated for chronic urticaria and explore the different factors influencing this duration and its outcome.