Food hypersensitivity in patients with pollen allergy.

Six hundred patients with pollen allergy answered a questionnaire about food hypersensitivity. Hypersensitivity to various nuts, fruits and roots was reported more often by patients with birch pollen allergy (70%) than by patients without birch pollen allergy (19%). The stronger the skin test reaction to birch pollen, the higher was the incidence of food hypersensitivity. A negative correlation was found between grass pollen allergy and food hypersensitivity. In the diagnosis of springtime hayfever, the presence of hypersensitivity to nuts, fruits and roots supports a diagnosis of birch pollen allergy.