Debates in allergy medicine: food intolerance does exist

Y. Vandenplas

Health care professionals and patients mix and mingle (hyper)sensitivity, allergy and intolerance. The consequences are discrepancies which result in confusion. The following is a very personal point of view, intended to start a debate to come to consensus. We aimed to clarify the proposed terminology for the primary health care professional from the point of view of the pediatric gastroenterologist. Many patients present with symptoms "related to food ingestion". We propose to use this wording if no underlying mechanism can be identified. Intolerance should be restricted to carbohydrate malabsorption causing symptoms. Allergy is restricted to IgE mediated allergy and non-IgE manifestations that can only be explained through an immune mediated mechanism, such as food induced atopic dermatitis and allergic colitis with blood in the stools. Unfortunately, primary heath care physicians have no diagnostic tools for non-IgE mediated allergy. A positive challenge test is a proof of a food-induced symptom, but does not proof that the immune system is involved. (Hyper)sensitivity suggests immune mediated mechanisms and should therefore not be used. The pathophysiologic mechanism of many food-related symptoms is unclear. The same symptom can be caused by allergy or be considered functional, such as infantile colic, gastro-esophageal reflux and constipation related to cow's milk ingestion in infants. In fact, "functional" is used if the pathophysiologic mechanism causing the symptom cannot be explained. Since the long term outcome of "allergy" differs substantially from "functional symptom", allergy should not be used inappropriate. "Food related symptom" should be used in each patient in which the pathophysiologic mechanism is not clear. Intolerance means a carbohydrate malabsorption that causes symptoms. Allergy should be used when the immune system is involved.