Corticosteroid responsive olfactory dysfunction in chronic rhinosinusitis: what does it mean?

Background: In the setting of chronic rhinosinusitis (CRS), olfactory improvement with corticosteroids suggests reversibility and preserved function. While self-rated olfactory function does not replace psychophysical measures of olfactory function, our goal is to investigate if self-reported pre-operative corticosteroid-responsive olfactory dysfunction (CROD) is a predictor of post-operative olfactory improvement in patients with CRS undergoing sinus surgery. Methodology: We performed a prospective, observational study of patients with refractory CRS with and without nasal polyposis and pre-operative olfactory dysfunction undergoing sinus surgery. Patients were characterized into corticosteroid-responsive and non-corticosteroid-responsive based on a survey response. Patient outcome measures for Sniffin Sticks, Olfactory Cleft Endoscopy Score (OCES), Questionnaire of Olfactory Disorders (QOD-NS), and Sino-nasal Outcomes Test (SNOT-22) were recorded pre- and post-operatively. Results: A total of 253 participants were included. Patients with CROD were more likely to have comorbid nasal polyposis, asthma, and aspirin sensitivity. Patients with CROD had significantly better post-operative improvement in OCES total scores and QOD-NS total scores compared to patients without CROD. Conclusions: In conclusion, patients with CRS and CROD are more likely to have a greater improvement in olfactory dysfunction post-operatively by several measures of olfactory outcomes. This suggests that corticosteroid responsiveness is a clinical predictor of preserved function and reversibility and can be used as a simple clinical prognostic factor.