Most of the current therapies for EoE are directed at decreasing esophageal allergic inflammation and mirror the treatment options for allergic asthma. Swallowed corticosteroids and elimination diets or elemental diets have shown variable efficacy is improving symptoms. However, specific pathophysiologic mechanism of EoE is still largely unknown and there is no definitive treatment that completely resolves symptoms and histological findings. Omalizumab is a recently developed anti-IgE antibody that has been shown to decrease the use of inhaled and oral corticosteroids and improve asthma related symptoms in patients with allergic asthma. In this study, Eosinophilic esophagitis is being used as a disease model to study the mechanism of action of monoclonal Anti-IgE antibody in vivo. The resolution of symptoms clinically, and histological changes (and improvements) in response to treatment with Xolair (omalizumab) in patients suffering from EoE will be determined. The primary objective of this open label, study is to determine mucosal markers that will predict responders to Omalizumab (Xolair).