What are some causes of bell's palsy?

Bell's Palsy: Causes include viral infections, medications, trauma, environmental factors, and metabolic or emotional disorders, thus suggesting that stress - emotional stress, environmental stress (e.g., cold), physical stress (e.g., trauma) - in short, a host of different conditions, may trigger bell's palsy.

Facial palsy: One of the most common triggers today of bell's palsy is lyme disease.

Unknown: The exact cause of bell's palsy is unknown but it is thought that it may be due to a viral infection of the facial nerve.