Allergy to pollen from different deciduous trees in Sweden. An investigation with skin tests, provocation tests and the radioallergosorbent test (RAST) in springtime hay fever patients.

92 adult patients with springtime allergy were investigated with skin tests, provocation tests and the RAST. Allergen extracts from 12 different deciduous trees were used. Positive reactions, often of high intensity, were most often found with birch, alder, bog-myrtle, beech and hazel allergens whereas oak, aspen, linden, elm, sallow, maple and poplar allergens more often gave negative or only weak positive test results. Cross sensitizations were found between botanically related as well as between less related species of the trees. Almost all patients with a clinically relevant tree pollen allergy had positive provocation tests with birch pollen. No patient had positive reactions to all the 12 allergens included in the study. 68% had positive provocation tests with the combination birch, alder and hazel. It is concluded that for diagnostic screening purposes it is sufficient to use birch pollen allergen. If the majority of relevant tree pollens are to be included in a diagnostic or therapeutic programme in Western Sweden it should contain birch, alder, hazel, beech and bog-myrtle allergens.