* Bell's palsy is the commonest cause
* pontine tumors and vascular events usually associated with other signs
**acoustic neuroma usually with evidence of other nerve involvement (V, VI, VIII nerves) at the cerebello-pontine angle
* Ramsay Hunt syndrome (herpes zoster infection)
* trauma
* middle ear infection and cholesteatoma
* sarcoidosis
* parotid gland tumors, trauma and infection
* HIV