Bell's (facial nerve) palsy

Bell's palsy is probably caused by herpes type 1 and herpes zoster virus

Early (before 72 hours) treatment with combined oral Acyclovir and Prednisolone is probably effective

1/5 cases of acute facial palsy have another cause that should be managed appropriately


A unilateral facial nerve palsy of sudden onset that is not associated with other cranial nerve abnormalities. The paralysis may be partial or complete.

Symptoms & signs

  • Most 5 - 45 years old   M=F
  • facial nerve neuro-anatomy
  • Incidence 20/100,000 [higher in pregnancy](1 in 60 people affected during their life)
  • Characteristically the patient wakes with a facial droop
  • Dribbling from the mouth - problems when eating
  • Changes in hearing (often hyperacousis on effected side) and taste
  • Fullness in ear or mild retroauricular pain (severe pain = Ramsey Hunt)
  • Exposure and drying of the cornea (also decreased tear production)
    • Check mouth and ear for vesicles(Ramsey Hunt syndrome)
    • Exclude trauma and parotid gland pathology
    • Slow onset, other nerve involvement or headache suggest other pathology
    • Facial N lesion with rash suggests Lyme disease
  • Some patients with Bell's have altered trigeminal sensation (not motor fxn), reduced C2 sensation and vagal motor weakness.
  • If in doubt please ask the ED Duty doctor for advice.


  • Cause unknown. Suspected viral infection leading to swelling of facial nerve in bony canal of skull.
  • Partial, uncomplicated palsy : no treatment required.
    • Complete recovery in vast majority
    • GP review in 10 - 14 days to ensure no progression to complete palsy
  • Complete palsy : may require early high dose steroids [Bandolier]
    • Prednisolone 1mg / kg (to max of 80mg) / day for 7 days (NNT 11) [BestBets]
    • IF early (< 72 hours) - and no vesicles treat with PO steroids alone [RCT NEJM 2007]
  • Vesicles present : start high dose antivirals (contact duty doctor for advice, then refer to neurology)
  • Inability to close eye on effected side - refer to ophthalmology
  • Acyclovir alone and surgery for facial nerve decompression are unproven.[Bandolier]
  • IN CUH, please refer all facial palsies to the next ED physio clinic (they will arrange early speech and language follow up).

Content drafted by Dr Jonathan Benger, Dr Íomhar O' Sullivan 13/03/2001. Reviewed by Dr ÍOS 03/09/2004, 07/07/2005, 14/04/2007. Last review Dr ÍOS 6/12/18