Platelet-rich plasma for the treatment of COVID-19 related olfactory dysfunction: a systematic review

Introduction: Olfactory Dysfunction (OD) is a prevalent issue with a significant number of cases attributed to COVID-19.This systematic review aimed to evaluate the effectiveness of platelet-rich plasma (PRP) in the treatment of COVID-19 related OD, including anosmia, hyposmia, and parosmia. Methods: A comprehensive literature search was conducted using Medline, Scopus, Directory of Open Access Journals (DOAJ), and Google Scholar from inception until December 22, 2022. The eligibility criteria were confirmed COVID-19 patients with OD, whether it was measured objectively and/or subjectively, who received PRP treatment. The study followed a pre-specified protocol registered in PROSPERO (ID: CRD42023386803) and adhered to PRISMA guidelines. Results: Four studies that enrolled 233 patients were included. The degree of improvement was assessed using threshold-discrimination-identification (TDI) scores at baseline and 1 and 2 months after PRP injection. Parosmia was assessed using the Visual Analog Scale (VAS) scores.Treatment of OD with PRP injections resulted in variable degrees of improvement. However, PRP injections can be considered safe, effective, and promising therapeutic options, as revealed by pooled studies. Conclusions: This systematic review indicated that PRP may be an effective treatment for COVID-19 related OD. However, additional large-scale studies are required to further investigate PRP efficacy in the treatment of OD following COVID-19.