The seasonal symptoms of hyposensitized and untreated hay fever patients in relation to birch pollen counts: correlations with nasal sensitivity, prick tests and RAST

Abstract

A 2 yr prospective study of 38 birch pollen-sensitive hay fever patients under specific immunotherapy and of 19 untreated control patients showed a significant correlation between the total seasonal symptom scores of the patients and their clinical sensitivities assessed by the RAST [radioallergosorbent test] and a graded nasal test. The agreement between a positive nasal test and a positive RAST was 74%. [There was a significant association of a positive prick test with a positive RAST.] In the early season with low pollen counts the onset of symptoms was significantly associated with high sensitivity of the patients, while many patients showed symptoms in the late season irrespective of their nasal and RAST sensitivity. About 90% of the treated and the untreated patients reported mild symptoms when the pollen count exceeded 80/m3 in the early season; 80% of them still had symptoms when the count was below 30/m3 in the late pollen season. Although hyposensitization therapy had no effect on the occurrence of the mild symptoms, the treated patients had severe symptoms significantly less often than the untreated ones on days with high pollen counts.