Self-reported food hypersensitivity in Sweden, Denmark, Estonia, Lithuania, and Russia.

AIM The main aim of the study was to describe the differences between some Northern countries regarding what foods, according to the patients, elicit hypersensitivity symptoms. METHODS At the participating clinics, patients with a history of food hypersensitivity (n = 1139) were asked to fill in a questionnaire in which 86 different foodstuffs were listed. Skin-prick tests (SPT) were performed with common inhalant allergens. RESULTS The foods that were reported as eliciting symptoms differed between countries. In Russia, Estonia, and Lithuania; citrus fruits, chocolate, honey, apple, hazelnut, strawberry, fish, tomato, egg, and milk were most often reported as causes of hypersensitivity. In Sweden and Denmark; birch pollen (BP) related foods, such as nuts, apple, pear, kiwi, stone fruits, and carrot were the most common causes. In all countries, children, more often than adults, had symptoms of allergic reaction to citrus fruits, tomato, strawberry, milk, egg, and fish. Most patients (95%) reported hypersensitivity to several foodstuffs (median: eight foods). The most common symptoms were oral allergy syndrome and urticaria. Severe symptoms were most common with fish, shellfish, nuts, and milk. Slight symptoms were most common with rice, coriander, poppy seed, lingonberry, corn, caraway red currant, and fig. Earlier well-known correlations, such as that between BP sensitization and some fruits and vegetables, as well as that between mugwort and some spices, were conoborated. Positive correlations were found between self-reported hypersensitivity to crustaceans and SPT with horse. A negative correlation was seen between hypersensitivity to crustaceans and SPT with BP. CONCLUSIONS The foodstuffs that often are reported to cause food hypersensitivity, differ between Sweden/Denmark on one side and the Baltic States and Russia on the other. BP-related foods dominate in Scandinavia, whereas some mugwort-related foods are of more importance in Russia and the Baltic States.