Certain factors have been seen to be frequently associated with Bell's Palsy:
- Inflammation of facial nerve: Inflammation, swelling or compression of facial nerve may result in Bell's Palsy.
- Viruses: Viral infections are the commonest causes of Bell's Palsy. Herpes simplex virus, Epstein-Barr virus and Cytomegalovirus are implicated in its development.
- Injury to facial nerve: Seventh cranial nerve (facial nerve) travels via a narrow, bony canal in the skull, beneath the ear, to the muscles on each side of the face. Though the nerve is encased in this bony shell for most of its course, yet any damage or trauma to it may result in Bell's Palsy.