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

facial nerve neuro-anatomy
  • Most 5 - 45 years old, M=F
  • 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 last review Dr ÍOS 15/06/21.