Mechanisms of food allergy.

Allergy type sensitization occurring in the gut results from a break in oral tolerance, mostly occurring in early childhood. In these patients, a minute amount of the large load of potential food allergens not only will result in immunoglobulin E (IgE) type sensitization mostly, but also in food allergies resulting from other mechanisms including eosinophil-driven disease or resulting from T-cell-mediated inflammation. Symptoms elicited by subsequent exposure to foods in these patients will be mostly in relation to the mechanism of the disease. In this educational review series, we described three cases of food allergy, first, a child with typical IgE-mediated food allergy, second, a child with eosinophilic proctocolitis and in the third patient, we will address tolerance acquisition mechanisms. These cases are discussed with regards to their specific immune events.