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. 2024 Oct 31;25(1):2.
doi: 10.1007/s11882-024-01182-6.

Treatment of COVID-19 Associated Olfactory Dysfunction: A Systematic Review

Sabrina Bischoff #  1   2 , Mathilde Moyaert #  1 , Marnick Clijsters  3 , Annabelle Vanderbroek  3 , Laura Van Gerven  4   5   6
Affiliations

Treatment of COVID-19 Associated Olfactory Dysfunction: A Systematic Review

Sabrina Bischoff et al. Curr Allergy Asthma Rep. .

Abstract

Purpose of review: COVID -19 associated olfactory dysfunction is widespread, yet effective treatment strategies remain unclear. This article aims to provide a comprehensive systematic review of therapeutic approaches and offers evidence-based recommendations for their clinical application.

Recent findings: A living Cochrane review, with rigorous inclusion criteria, has so far included 2 studies with a low certainty of evidence. In this systematic review we list clinical data of 36 randomised controlled trials (RCTs) and non-randomised studies published between Jan 1, 2020 and Nov 19, 2023 regarding treatment options for COVID-19 associated olfactory dysfunction. Nine treatment groups were analysed, including olfactory training, local and systemic corticosteroids, platelet-rich plasma (PRP), calcium chelators, vitamin supplements including palmitoylethanolamide with luteolin, insulin, gabapentin and cerebrolysin. Primary objective was the effect of the studied treatments on the delta olfactory function score (OFS) for objective/psychophysical testing. Treatments such as PRP and calcium chelators demonstrated significant improvements on OFS, whereas olfactory training and corticosteroids did not show notable efficacy for COVID-19 associated olfactory dysfunction.

Keywords: COVID-19; Olfactory dysfunction; Treatment.

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Conflict of interest statement

HippoDx (stocks and scientific advisory board), speakers fees from GSK.

Figures

Fig. 1
Fig. 1
Prisma flow-chart (From: Page MJ, McKenzie JE, Bossuyt PM, Boutron I, Hoffmann TC, Mulrow CD, et al. The PRISMA 2020 statement an updated guideline for reporting systematic reviews. BMJ 2020;372:n71. https://doi.org/10.1136/bmj.n71)
Fig. 2
Fig. 2
Forest plot of the effect of (A) olfactory training, (B) intranasal corticosteroids (ICS) and (C) systemic corticosteroids (CS). The studies are categorized based on the duration of smell loss before the treatment, split into 3 subgroups: less than 3 months, between 3 to 6 months, and more than 6 months
Fig. 3
Fig. 3
Forest plot of the effect of (A) platelet-rich plasma (PRP), (B) palmitoylethanolamide and luteolin (PEA-LUT) and (C) calcium chelators
See this image and copyright information in PMC

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