[Allergic and pseudoallergic reactions of the urticaria skin and mucous membranes due to food components with special reference to food and RAST].

Among 1.000 consecutive cases of urticaria with suspicious food history and positive oral exposition, 12 patients showed an acute recurrent course. The result of the Prick or rub test was mainly positive in analogy, the RAST later determined in 5 of these patients remained four times "false negative" to the rub test in 4 of 5 allergens. Many of these patients complained of typical mucosal prodromes immediately on oral exposition, which are apparently pathognonomic of food allergy. In another 13 patients, the clinical reaction was limited to oral symptoms without generalized urticaria, in spite of corresponding history and skin tests; therefore, it was regarded as "forme fruste anaphylaxis". In these cases RAST was performed together with the Prick or rub test; seven times it corresponded with the oral exposition, five times it remained negative. In correspondence with the Prick test it was five times positive and two times negative; it remained "false negative" to 9 allergens. Remarkable in this group was the coincidence of positive apple RAST and strongly positive birch pollen allergy in the form of rhinitic or asthmatic symptoms and atopy. Among 72 patients with chronically-recurrent urticaria and no suspicious history, however, there was only one case of nutritive allergy demonstrated by means of elimination and provocation diet and a subsequent "super meal". On the other hand, pseudoallergic intolerance reactions (of the aspirin type) to food additives were demonstrated in 14 out of 300 patients with chronic urticaria my means of systematic oral provocation. Therefore, in cases of chronic urticaria with no suspicious history, there is no much use in searching for a nutritive allergen by means of elimination or provocation diet, in contrast to the intolerance diagnosis by certain "test batteries". In total, the rate of secured food allergies in patients with urticaria (without "forme fruste anaphylaxis") was approximately 1.5%, the rate of pseudoallergic reactions to food additives was 4.7%. Taking together all cases, an involvement of causative or partly causative food components was demonstrated in 8.6%.(ABSTRACT TRUNCATED AT 400 WORDS)