A Brazilian multicenter pilot case series on the efficacy of photobiomodulation therapy for COVID-19-related taste dysfunction

Photodiagnosis Photodyn Ther. 2022 Mar;37:102643. doi: 10.1016/j.pdpdt.2021.102643. Epub 2021 Nov 24.


Background and aim: Among the most common symptoms of COVID-19 is taste dysfunction, which has a ranging clinical presentation. As well as its pathophysiology remains to be unclear, there is not enough information about the efficacy and safety of the available treatments. This study aims to report a series of cases using PBMT for the management of COVID-19-related taste impairment.

Case series: 8 female and 2 male patients sought medical help for taste impairment (either partially or completely) after COVID-19 infection. Photobiomodulation therapy (PBMT) on the tongue mucosa was then proposed but with 3 different protocols. Taste perception at baseline and before every laser session was evaluated using a visual analog scale. Irrespective of the PBMT protocol, taste recovery was noted in all cases but with varying degrees of improvement.

Conclusion: given the high prevalence rates of taste dysfunction in COVID-19 patients and the lack of information about the available treatments, PBMT seems to be a promising therapeutic modality but not dependent on the total number of laser sessions and the interval between them. The choice of the most suitable laser protocol as well as the knowledge of the exact photonic mechanisms, however, need to be better studied.

Keywords: COVID-19; SARS-CoV-2; lasers; low-level light therapy; taste perception.

Publication types

  • Multicenter Study

MeSH terms

  • COVID-19*
  • Female
  • Humans
  • Low-Level Light Therapy* / methods
  • Male
  • Photochemotherapy* / methods
  • SARS-CoV-2
  • Taste Disorders / etiology