Pathophysiology

Herpes simplex virions

The cause of Bell’s palsy has long been debated but only recently has evidence started to accumulate for a viral origin.

Reactivation of latent herpes simplex or zoster virus is the most likely scenario, as shown in the image.

Herpes virus DNA has been isolated from facial nerve endoneural fluid [5], however attempts to isolate herpes simplex DNA from cerebrospinal fluid (CSF) and saliva in facial palsy patients, have been less successful [6,7].