Analysis of olfactory function in patients with chronic rhinosinusitis and Staphylococcus aureus enterotoxin positivity

To investigate disparities in sensitisation to Staphylococcus aureus enterotoxin A/B (SEA/SEB) and olfactory function in patients with chronic rhinosinusitis (CRS) with nasal polyps (CRSwNP), those with CRS without nasal polyps (CRSsNP), and healthy controls who underwent septoplasty only. We retrospectively reviewed the medical records of 388 subjects aged >= 8 years, collected between January 2021 and June 2023. We analysed patient demographics, medical history, serum IgE levels against staphylococcal enterotoxins (SEs), and serum total IgE levels against inhalant allergens. We performed olfactory and taste function tests in the participants to evaluate the relationship between olfactory function and SEs. Of 388 patients enrolled, 145 were healthy controls, 111 had CRSsNP, and 133 had CRSwNP. The prevalence of SEA/SEB positivity was significantly higher among the patients with CRSwNP than among those in the CRSsNP and healthy controls. The olfactory test results showed significant differences among the groups; anosmia was observed in 9.7% of healthy controls, 22.7% of patients with CRSsNP, and 45.1% of patients with CRSwNP. Olfactory threshold deterioration was evident in patients with CRS. Distinction and identification were more impaired in patients with CRSwNP than in those of the other groups. Finally, the olfactory function scores decreased as the serum levels of SEs increased. Sinusitis patients seem to suffer from perceiving odours, and patients with CRSwNP have difficulty distinguishing odours. Olfactory function test scores decreased in patients with a history of asthma, and as serum levels of staphylococcus enterotoxin and blood eosinophil percentage increase. Furthermore, our result suggests a potential role for SE sensitisation and eosinophil percentage in deteriorating olfaction, especially in patients with CRSwNP.