[Allergen challenge used to diagnose food allergy--oral allergy syndrome]

Food allergy is an immune mediated unwanted side effect to food. All types of hypersensitivity can be involved; the most prevalent is IgE mediated one. The diagnosis is based on the history, skin tests with allergens and detection of specific IgE. These procedures are not highly predictive for clinical reactivity to food allergens, true clinical reactivity can be confirmed by allergen challenge. Oral allergy syndrome is represented by mostly subjective symptoms in oral cavity, usually triggered by fruit or vegetable allergens, cross-reacting with pollen allergens. This cross-reactivity is based on protein homology and immunologic similarity. To confirm the diagnosis of food allergy, the ,,golden standard" is the double blind placebo controlled food challenge. The basic features of this test are discussed, particularly in the diagnosis of the oral allergy syndrome. Controlled food challenge is a useful test for patient's diagnosis confirmation, evaluation of other diagnostic tests or evaluation of food allergenicity.