Identifying Olfactory Phenotypes to Differentiate Between COVID-19 Olfactory Dysfunction and Sinonasal Inflammatory Disease.

The objective of this study was to identify specific olfactory phenotypes-patterns of olfactory performance-across distinct cohorts with or without olfactory dysfunction (OD). Adult patients underwent testing via a novel olfactory testing methodology in 1 of 4 groups based on health status: sinonasal inflammatory condition (chronic rhinosinusitis or allergic rhinitis), ≥4 weeks of self-reported OD after resolved COVID-19 infection, Alzheimer's disease, and healthy control. Participants' scores for each scent were normalized on a scale of 0 to 1 relative to their worst and best scores. Agglomerative hierarchal cluster analysis was performed on normalized data for the COVID-19 and sinonasal cohorts. Resulting clusters from the penultimate merger revealed a sensitivity of 81% and specificity of 63% for the detection of patients with COVID-19. These results support that there are olfactory phenotypes that may discriminate COVID-19 OD from sinonasal inflammatory disease. These phenotypes will likely become increasingly leveraged in the workup and treatment of patients with OD.