When bound to the high-affinity IgE receptor (FCERI), IgE acts as an environmental sensor that detects allergens and induces allergic responses from the cell's interior. Omalizumab is a monoclonal antibody that binds free IgE preventing it from binding to FCERI. Moreover, reduction of free IgE concentrations reduce FCERI expression level. Omalizumab is approved for the treatment of patients with severe allergic asthma. Use of omalizumab is associated with several side effects, including injection site reactions, viral and upper respiratory tract infections, headache, sinusitis, and pharyngitis. The main severe adverse effect is anaphylactic shock, with a rate of occurrence of 1 to 2 patients per 1,000 (Davydov 2005, Arm et al. 2014).