Laboratory and clinical investigations over the past two decades have demonstrated that food allergy plays a pathogenic role in a subset of patients, primarily infants and children, with atopic dermatitis (AD). Approximately 40% of infants and young children with moderate to severe AD have food allergy, but identifying this subset of patients and isolating the relevant food allergens requires a high index of suspicion, the use of appropriate laboratory tests, and, in some cases, physician-supervised oral food challenges. Removal of the causal food protein(s) leads to clinical improvement but requires a great deal of education because most of the common causal foods (egg, milk, wheat, soy, peanut, and so forth) are ubiquitous in the food supply, and food elimination diets risk causing nutritional deficits. Fortunately, most food allergies resolve in early childhood, and food allergy is not a common cause for AD in older children and adults.