High levels of Olea europaea pollen and relation with clinical findings

Background: Olea europaea pollen is an important cause of seasonal allergic rhinitis and bronchial asthma in southern Spain. For patients allergic to grass pollen the critical concentration of airborn pollen is 50 grains/m(3), but in the case of Olea pollinosis no data is available. Methods: Fifty-six seasonal allergic rhinitis patients (29 in 1994 and 27 in 1995) were included in this study, all of whom lived in Jaen. Daily symptom card were filled in and pollen counts during May and June were performed in both years. A linear regression model was used for analysis of the airborne pollen concentration and the symptom score. Results: Significant correlations among daily counts of Olea pollen and rhinitis symptoms were obtained. Most of our monosensitized patients needed a high Olea pollen concentration in the atmosphere (around 400 grains/m(3)) to suffer at least from mild allergic rhinitis symptoms. Conclusion: Local conditions with a wide a rea dedicated to olive tree cultivars result in a high concentration of this pollen in the atmosphere, Monosensitized Olea patients in our area seem to need exceptionally high levels to suffer from allergic symptoms.