[Food allergies].

Abstract

Food allergy must have an immunological background. Till recently it was restricted only to the IgE mechanism, today we include also non-atopical reactions (in particular type III and IV according to Coombs and Gell). We speak of probable and possible food allergies. By differential diagnosis we must differentiate food allergies from food intolerance (e.g. enzyme deficiencies), food aversions (psychic factor) as well as toxic and pharmacological effects. There are more than 10% undesirable reactions in humans after ingestion of food but only every fifth (some 2% of the population have food allergies. The diagnosis is based above all on the case-history, subsequent elimination and exposure tests and examination by allergological tests, or examination of specific immunoglobulins E (IgE). The diagnosis is not always unequivocal--it is influenced among others by a different specificity and sensitivity of food antigens (allergens). The manifestations of food allergy are found at the site of action (mouth, GIT) or are systemic (respiration, cardiovascular system, skin etc.). A special type of food allergy is the oral alimentary syndrome, i.e. food allergy crossed with pollen hypersensitivity, described in the great majority of subjects sensitive to pollen. Food allergy has its specific age-conditioned and geographical features. In childhood sensitivity to the protein of cows milk, egg white but also soya or flour predominates, with advancing age allergies to nuts, fruit, vegetables, spices, cheese, sea foods increase. Food allergy can be a very early allergy (manifested already in infant age) but it is one of the few allergies which can also recede (incl. laboratory tests). Treatment is dietetic, the period of dietetic treatment depends on the type of food and the patient's age, not infrequently it must be lifelong. If diet does not suffice, preventive medication is used (sodium cromoglycate) or symptomatic (antihistamine preparations, corticosteroids, external agents etc.), in some countries specific immunotherapy is being tested.