Relationship Between Serum Inflammatory Markers and Olfactory Function in Polypoid and Non-Polypoid Chronic Rhinosinusitis

<strong>Objective:</strong> This study aimed to investigate the association between serum inflammatory markers, partic0 ularly the Systemic Immune0Inflammatory Index (SII), and disease severity and olfactory function in patients with chronic rhinosinusitis (CRS). <strong>Materials and Methods:</strong> A total of 59 CRS patients and 29 healthy controls were included. Patients were categorised as CRSsNP (n=30) or CRSwNP (n=29). Olfactory function was assessed with the Sniffin’ Sticks test, whereas disease severity was evaluated using the Lund–Kennedy endoscopic and Lund–Mackay radiological staging systems. Quality of life was measured using the SNOT022 questionnaire. Inflammatory indices, including NLR, PLR, ELR, and SII, as well as eosinophil counts and total serum IgE levels, were analysed. <strong>Results: </strong>Compared with controls, CRSwNP patients demonstrated significantly higher eosinophil counts and ELR values (p&lt;0.001). No significant differences were observed for IgE, NLR, PLR, or SII levels between the groups (p=0.248). Olfactory scores showed a significant negative correlation with both radiological and endoscopic staging. Importantly, systemic inflammatory indices such as SII and NLR were not associated with olfactory dysfunction, suggesting their limited diagnostic utility in CRS. <strong>Conclusion: </strong>While most systemic inflammatory indices did not correlate with olfactory performance or disease severity, ELR and eosinophil counts were markedly elevated in patients with CRSwNP, highlighting the potential disease0specific relevance of ELR in CRS0related olfactory dysfunction.&nbsp;