Olfactory Dysfunction in Allergic Rhinitis

Abstract

Background: Olfactory dysfunction in patients with allergic rhinitis has long been thought to be secondary to coexisting chronic rhinosinusitis and polyposis with obstruction of airflow over the olfactory epithelium. Recent evidence suggests that the allergic inflammatory infiltrate may itself affect olfaction in the absence of mucosal hypertrophy. Objective: We undertook a study to determine olfactory function in patients with allergic rhinitis in the presence and absence of chronic sinusitis. Methods: Fifty-one subjects with symptoms of rhinitis who presented for allergy testing were administered the University of Pennsylvania Smell Identification Test. In addition each patient underwent computed tomography (CT) scanning of the sinuses. Results: Eighty percent of subjects were allergic. Subjects with allergic rhinitis and no evidence of sinusitis scored on average in the 30th percentile (95% CI 20–40th percentile) on objective olfactory testing compared to age- and gender-specific norms. Half the allergic patients were classified as normosmic, while half had some degree of hyposmia. Conclusions: Our study demonstrates that even in the absence of mucosal disease on CT scan, a significant subset of patients with allergic rhinitis will exhibit hyposmia, mostly to a mild or moderate degree. The pathophysiology and potential treatments for olfactory loss in these patients should be further explored.

Olfactory dysfunction in seasonal and perennial allergic rhinitis

“…Olfactory function was decreased in threshold, discrimination, and identification testing in patients with seasonal or perennial AR, which is in good accordance with other published studies [3,11]. Levels of ECP were significantly elevated in our patients, with seasonal AR being in line with comparable data published by Klimek et al [4], who showed eosinophilic inflammation of the nose after 3 weeks after the beginning of allergy season and Kramer et al [12] who compared ECP levels of different chronic nasal inflammatory diseases.…”

“…Is it the whole inflammatory milieu with a mixture of different mediators from different kinds of cells or is it a single mediator leading to this lack of olfactory function? Current studies in humans [11] and in an animal model using allergic mice [15] showed an infiltration of eosinophils, neutrophils, mast cells, plasma cells, and macrophages in the olfactory mucosa. So far the available studies have mainly focused on the role of eosinophilic cells and their main toxic mediator in AR ECP.…”

Olfaction in allergic rhinitis: A systematic review

“…As already mentioned above, Guss et al 54 showed in a small group of 31 patients with AR that 48% had measured olfactory dysfunction. However, none of their patients exhibited anosmia, indicating that olfactory dysfunction was not severe.…”

Multi-morbidities of allergic rhinitis in adults: European Academy of Allergy and Clinical Immunology Task Force Report

“…This is probably secondary to a local inflammation in the nasal fossa and around the olfactory neuroepithelium in the olfactory cleft rather than a nasal obstruction impairing the odours to reach the olfactory cleft [82]. …”