The Role of Herpes Simplex Virus in the Etiology of Bell's Palsy
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Abstract
Background: Bell's palsy, the most common cause of acute peripheral facial paralysis, is strongly associated with reactivation of latent herpes simplex virus type 1 (HSV-1) in the geniculate ganglion. Through PRISMA-guided review we evaluated the molecular and clinical evidence for this association.
Methods: A systematic search of major electronic databases (PubMed, ScienceDirect, Google Scholar) was conducted for studies published up to December 2025. The PICO framework guided inclusion criteria, focusing on studies assessing HSV infection in Bell's palsy patients compared to controls, and reporting on HSV-1 DNA detection or antiviral efficacy. Molecular methods including PCR and serological assays were acceptable. The quality was assessed using the Newcastle-Ottawa Scale and the Cochrane Risk of Bias tool.
Results: Twenty-three studies met the inclusion criteria. Molecular analyses consistently detected HSV-1 DNA in the geniculate ganglia and peripheral fluids of patients, with detection rates up to 79% in endoneurial fluid. Epidemiological data confirmed a strong association (odds ratio: 6.49; 95% CI: 5.96-7.05). However, evidence regarding the efficacy of adjuvant antiviral therapy combined with corticosteroids remained inconsistent. Major systematic reviews demonstrated no significant clinical benefit for the general population, with combination therapy increasing recovery by a maximum of 7%.
Conclusion: Strong molecular and epidemiological evidence supports HSV-1 reactivation as a major etiological factor in Bell's palsy. However, the routine clinical benefit of concomitant antiviral therapy remains unproven for the overall population. Future management should prioritize diagnostic stratification using viral PCR testing and severity classification to identify virus-induced cases benefiting most from targeted antivirals.
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