Surge of Bell palsy in the era of COVID-19: Systematic review

With the progression of coronavirus infectious disease 2019 (COVID-19), various neurological manifestations have been noticed in infected patients, and Bell palsy (BP) is one of the peripheral neuropathies among those. BP has been associated with various other viral agents. Its evidence in patients with COVID-19 signifies the possibility of association between BP and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This research was undertaken to evaluate the number of published cases of BP as the only major neurological manifestation in patients with COVID-19 from March 2020 to December 2021 and to investigate the association of SARS-CoV-2 and BP. A systematic review of the published English literature was performed using an electronic search in the PubMed/Medline, Scopus, Research Gate, Research Square, and Google Scholar databases, using keywords such as "COVID-19" OR/AND "SARS-CoV-2" OR/AND "Bell's palsy" OR/AND "facial nerve palsy" OR/AND "neurological" OR/AND "manifestation". The search strategy revealed 32 relevant publications with a total of 46 patients. BP was the initial manifestation in 37% of cases, and in 63% of cases it developed after COVID-19 symptoms; 71.7% of cases showed complete recovery, and 21.7% showed only partial relief from BP. Although the number of documented cases in this research is low, evidence of BP as the only major neurological manifestation in patients with COVID-19 signifies an important clinical finding and the possibility of another viral etiology of BP. More evidence is needed to establish the exact correlation between these two entities.