The Effects of Olfactory Training with Intranasal Corticosteroid Spray in Korean Patients with Olfactory Dysfunction

Abstract

Background and Objectives: Olfactory training is an alternative treatment based on modulation of the regeneration process of the olfactory system via repeated exposure to odors. Our study aimed to investigate the impact of olfactory training with intranasal corticosteroid in Korean patients with various causes of olfactory dysfunction. Subjects and Method: Our study population comprised 134 adults with olfactory dysfunction of different etiologies (postviral infection n=85; post-traumatic n=18; and idiopathic n=31). For training, patients exposed themselves to four different odors twice a day. All patients used fluticasone nasal spray (two sprays in each nostril once daily). Olfactory function was evaluated at baseline and again at three months, and results were quantified as patient TDI (threshold, discrimination, and identification) score. Results: Olfactory function improved in 74 of 134 patients (55.2%). Etiology of olfactory disorder, sex, and age had statistically significant influence on the improvement rate of olfactory function, among which etiology of olfactory loss was the most important. However, initial severity and duration of olfactory loss had no statistically significant influence on the improvement rate. The TDI score at three months of olfactory training showed remarkable improvement, primarily because of improvements in the discrimination and identification components. Conclusion: The present study showed that olfactory training with intranasal corticosteroid was beneficial to improve olfactory function in patients with olfactory dysfunction, particularly in postviral infection patients.

Effects of olfactory training on posttraumatic olfactory dysfunction: a systematic review and meta‐analysis

“… 31 , 38 , 42 , 43 The proportion of clinically significant results in patients with combined treatment can reach up to 33% to 50%, which is higher than that in the olfactory training group. 38 , 42 , 43 Anti‐inflammatory treatment with steroids improved neuronal recovery following olfactory nerve transection via suppression of the inflammatory reaction and reduction of glial scar formation. 14 This may explain why corticosteroids combined with olfactory training are more effective.…”

“…1 ). Thirteen articles met the criteria for qualitative analysis 29 , 30 , 31 , 32 , 33 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 and 6 of these were included in the meta‐analysis. 29 , 30 , 31 , 32 , 33 , 36 All 13 articles reported the distribution of sex, a total of 565 females and 403 males, skewing toward female patients.…”

“…Four articles were randomized controlled trials, 29 , 37 , 38 , 39 assessed by the Cochrane Collaboration's tool, which was shown in Figure 2 . Nine articles were cohort studies, 30 , 31 , 32 , 33 , 36 , 40 , 41 , 42 , 43 assessed by the Newcastle‐Ottawa Scale (Table 3 ). The main sources of bias in these studies were ascertainment of exposure and comparability.…”

“…Olfactory training together with local or systematic steroid has been utilized for the treatment of posttraumatic olfactory dysfunction 31,38,42,43 . The proportion of clinically significant results in patients with combined treatment can reach up to 33% to 50%, which is higher than that in the olfactory training group 38,42,43 . Anti‐inflammatory treatment with steroids improved neuronal recovery following olfactory nerve transection via suppression of the inflammatory reaction and reduction of glial scar formation 14 .…”