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Review
. 2024 Apr 18;25(8):4460.
doi: 10.3390/ijms25084460.

Olfactory Loss in Rhinosinusitis: Mechanisms of Loss and Recovery

Agnès Dekeyser  1 , Caroline Huart  1   2 , Thomas Hummel  3 , Valérie Hox  1   2
Affiliations
Review

Olfactory Loss in Rhinosinusitis: Mechanisms of Loss and Recovery

Agnès Dekeyser et al. Int J Mol Sci. .

Abstract

Chronic rhinosinusitis (CRS) is a highly prevalent disease and up to 83% of CRS patients suffer from olfactory dysfunction (OD). Because OD is specifically seen in those CRS patients that present with a type 2 eosinophilic inflammation, it is believed that type 2 inflammatory mediators at the level of the olfactory epithelium are involved in the development of this olfactory loss. However, due to the difficulties in obtaining tissue from the olfactory epithelium, little is known about the true mechanisms of inflammatory OD. Thanks to the COVID-19 pandemic, interest in olfaction has been growing rapidly and several studies have been focusing on disease mechanisms of OD in inflammatory conditions. In this paper, we summarize the most recent data exploring the pathophysiological mechanisms underlying OD in CRS. We also review what is known about the potential capacity of olfactory recovery of the currently available treatments in those patients.

Keywords: chronic rhinosinusitis; olfaction; olfactory dysfunction.

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Conflict of interest statement

The authors declare no conflicts of interest.

Figures

Figure 1
Figure 1
Distribution of olfactory loss aetiologies. Percentages of OD causes in patients treated in different German, Austrian, and Swiss ENT clinics. Adapted from Damm, Schmitl [5].
Figure 2
Figure 2
Possible disease mechanisms of OD in CRS. Possible mechanistic pathways that can explain the OD observed in CRS patients, based on available scientific data. OBPs: olfactory binding proteins. MVC: microvillar cells. SUS: sustentacular cells. OSNs: olfactory sensory neurons. GBCs: globose basal cells. HBCs: horizontal basal cells. TH: T helper. ILC2: type 2 innate lymphoid cells. IL: interleukin. IFNγ: interferon-γ. TNF-α: tumour necrosis factor α. MBP: major basic protein. EPO: eosinophil peroxidase. ECP: eosinophil cationic protein. OSM: oncostatin M. GM-CSF: granulocyte-macrophage colony-stimulating factor. Created with BioRender.com.
See this image and copyright information in PMC

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