PREVALENCE OF IGE ANTIBODIES SPECIFIC FOR FOOD ALLERGENS IN PATIENTS WITH CHRONIC URTICARIA OF UNEXPLAINED ETIOLOGY

We investigated whether some cases of chronic urticaria of unexplained cause might be related to food allergy which had remained undetected during routine examination. This investigation was undertaken as the c onsequence of the availability of a new in vitro assay for specific Ig E with increased sensitivity. The following three groups of subjects w ere studied: 1) a control group of 60 nonatopic subjects, 2) 60 patien ts with allergy to perennial aeroallergens without skin involvement, a nd 3) 60 patients suffering from chronic urticaria with no evidence of any triggering factor despite careful clinical investigation. Specifi c IgE against 19 food allergens frequently involved in urticaria were investigated in all subjects with the new CAP System (Pharmacia). Posi tive results (CAP > 0.70 kU/l) for one or more food allergens were fou nd in none of the nonatopic controls, in six of the subjects with resp iratory allergy, and in 16 of the urticaria patients. The use of an in vitro test with an increased sensitivity allowed us to detect a signi ficant prevalence of IgE specific for food allergens in patients with chronic urticaria of unknown origin. This suggests that, in several of those patients, chronic urticaria might be triggered by a food allerg y undetected by the usual methods.