Differentiating food allergies from food intolerances

Adverse reactions to foods are extremely common, and generally they are attributed to allergy. However, clinical manifestations of various degrees of severity related to ingestion of foods can arise as a result of a number of disorders, only some of which can be defined as allergic, implying an immune mechanism. Recent epidemiological data in North America showed that the prevalence of food allergy in children has increased. The most common food allergens in the United States include egg, milk, peanut, tree nuts, wheat, crustacean shellfish, and soy. This review examines the various forms of food intolerances (immunoglobulin E [IgE] and non-IgE mediated), including celiac disease and gluten sensitivity. Immune mediated reactions can be either IgE mediated or non-IgE mediated. Among the first group, Immediate GI hypersensitivity and oral allergy syndrome are the best described. Often, but not always, IgE-mediated food allergies are entities such as eosinophilic esophagitis and eosinophilic gastroenteropathy. Non IgE-mediated immune mediated food reactions include celiac disease and gluten sensitivity, two increasingly recognized disorders. Finally, non-immune mediated reactions encompass different categories such as disorders of digestion and absorption, inborn errors of metabolism, as well as pharmacological and toxic reactions.