[Classification of food allergy: generalities]

The prevalence of food allergy has increased in some regions of the world, and with it the incidence, according to geographical variability, in the phenotype and clinical manifestations. Food allergy arises from the specific immune response induced by exposure to the proteins of a certain food. Food intolerance refers to non-immune reactions, caused by unique physiological characteristics of the individual, including metabolic, toxic, pharmacological and undefined mechanisms. Adverse reactions to foods are classified as: IgE-mediated: Type I Hypersensitivity, non-IgE-mediated: Type IV Hypersensitivity, mixed: Types I and IV Hypersensitivity Non-Allergic; toxic, pharmacological, metabolic, intolerances. These types of alterations are rare but have increased in recent years; These include protein-induced enterocolitis syndrome, which can cause emesis, diarrhea and hypotension, and shock, which begins two hours after ingestion of the allergen. Protein-induced allergic proctocolitis is a condition that includes allergy to cow's milk protein. Delayed reactions usually affect the digestive system, are more insidious in their onset and are not immediately controlled, even with the suspension of food. There are eight foods responsible for 90% of food allergies: milk, eggs, soy, wheat, peanuts, walnuts, fish, and shellfish.