IgE-mediated food allergy: classification based on the way of sensitization

Food allergies are usually classified based on the immunological mechanism. This classification does, however, not explain the age dependent differences in disease frequency and pattern of predominant food allergens, nor the different stability of food allergens to digestive processes. Based on the concept that the way of sensitization to food proteins is different between small children and adults, a new classification of IgE mediated food allergy is proposed: Food allergy type A represents the food allergy of infants and small children, which get sensitized to chemically relatively stable food proteins via the gastrointestinal tract. Symptoms frequently disappear concomitantly with the maturation of the gastrointestinal barrier and oral tolerance. Food allergy type B is due to crossreactivities of IgE, which is originally directed to aerogeneous allergens in pollen, latex etc.: It is the most frequent food allergy in older children, adolescents and adults: Respiratory symptoms to the sensitizing aerogenous allergen preceed the food allergy, but must not always be pre sent. Food allergy (urticaria, anaphylaxis, oral allergy syndrome etc.) develops mainly to fruits, nuts and vegetables, which contain proteins recognized by the preformed, pollen- or latex-allergen reactive IgE. The crossreactive food allergen may not be chemically stable, but the degree of stability determines the type and localizaton of food related symptoms. Food allergy type C is rare. In contrast to type A and B reactions, is does not appear predominantly in atopic persons. The majority of affected persons are females, which get sensitized via the gastrointestinal tract to selected, stable food proteins. The proposed classification may resolve contradictory findings and thus help to better understand food allergy. Moreover, it has implications for the discussion of the allergenicity of gen-modified food and for the obligatory use of double blind, placebo controlled food challenge (DBPCFC) in the diagnosis of food allergy.