ADVERSE REACTION TO FOOD - ASSESSMENT BY DOUBLE-BLIND PLACEBO-CONTROLLED FOOD CHALLENGE AND CLINICAL, PSYCHOSOMATIC AND IMMUNOLOGICAL ANALYSIS

Double-blind placebo-controlled food challenge (DBPCFC) with food item s applied in capsules was performed in a prospective study of 17 selec ted patients and 34 age- and sex-matched healthy controls in the inter disciplinary clinical setting. Protein immunoblotting showed no differ ences in antigenicity between foods in the capsules and the correspond ing fresh foods. All patients reacted to one or more food substances d uring DBPCFC, with a doubtful reaction to placebo in 2 patients. Agree ment between diet history and provocation was seen in 53 of 85 individ ual food challenges, 36 being positive with both examinations. In 22 ( 38%) of the 58 positive provocations, the reactions were not expected from the patients' histories. No reaction to food or placebo occurred in the control group. Related to diet history, sensitivity and specifi city of provocation were 62 and 63%, respectively, with a positive pre dictive value of 78%. Allergy, previous gastroenterologic and infectio us diseases among first-degree relatives, immunologic abnormalities an d elevation of total IgE were significantly more common for the patien ts than controls. A positive skin prick test correlated well with diet history, but both prick test and food antibodies correlated poorly wi th DBPCFC. Assessment by the General Health Questionnaire showed a sig nificant difference towards the controls. After 3-4 months of follow-u p on an individually based diet, 11 of 15 patients reported general im provement of their condition. DBPCFC may be a valuable diagnostic test in addition to dietary history as a basis for elimination diet in foo d-intolerant patients. The effect of the elimination diet on the sympt oms may also suggest a therapeutic effect or provocation. The interdis ciplinary characterization of a selected group of food-intolerant pati ents suggests a multifactorial etiopathogenesis behind this diagnosis.