OLFACTORY DYSFUNCTION IN ALLERGIC RHINITIS IS RELATED TO NASAL EOSINOPHILIC INFLAMMATION

Background: Olfactory dysfunction is a common finding in patients suff ering from allergic rhinitis. However, little is known about the patho physiology underlying this phenomenon and about the time course of hyp osmia in seasonal allergy. Methods: A prospective controlled study was performed on 17 patients with allergic rhinitis to grass pollen in or der to evaluate olfactory function in correlation to the duration of a llergen exposition, symptoms, eosinophil cationic protein (ECP) in nas al secretions, and nasal volume flow (NVF), Olfactory function was eva luated preseasonally and on days 3, 7, 14, and 21 of the season using a modified Connecticut Chemosensory Clinical Research Center testing p rocedure for threshold, identification, and discrimination. Twelve vol unteers without allergy served as controls. Results: Preseasonally, pa tients and controls performed equally in discrimination and identifica tion testing, but not in threshold testing. No changes were found in t he controls, but a significant decrease in threshold and identificatio n from the 7th day of the season in patients with allergy was noted th at was better correlated to ECP than to NVF. NVF was already maximally decreased from the 3rd intraseasonal day with no further changes, ECP increase became significant at day 14. Conclusion: Patients with gras s pollen allergy develop olfactory dysfunction during natural allergen exposure that might be related to allergic inflammatory mechanisms.