There are approximately 15 million Americans, including 6 million children, who have a potentially life-threatening food allergy. The prevalence of this disease has increased over the last three decades, in both the United States and other developed countries. There are no cures or effective prevention or treatment strategies for food allergy. Moreover, little is known about the factors that account for the rising prevalence and severity of these diseases in recent years. Both genetic and environmental factors likely contribute to the development of food allergy, but the complex interaction between these variables has frustrated efforts to elucidate pathogenesis and develop mechanism-targeted therapies. Children with food allergy are 2 to 4 times more likely to be diagnosed with asthma or other allergic conditions than children without food allergy, and food allergy may also be an important trigger for atopic dermatitis and eosinophilic esophagitis. The Laboratory of Allergic Diseases within the National Institute of Allergy and Infectious Diseases has a longstanding interest in the genetics and pathogenesis of allergic inflammatory disorders, and with the National Institutes of Health Clinical Center, it provides the ideal environment for the proposed translational studies. In this study, we will: (1) investigate the key genetic, cellular, immunologic, and biochemical pathways that lead to the development of food allergy, and (2) identify biomarkers that predict the clinical course and natural history of patients with food allergy.