Bell's palsy

Last reviewed: 20 Feb 2023
Last updated: 07 Jun 2022



History and exam

Key diagnostic factors

  • single episode
  • unilateral
  • absence of constitutional symptoms
  • involvement of all nerve branches
  • keratoconjunctivitis sicca
  • pain
  • synkinesis
More key diagnostic factors

Other diagnostic factors

  • presence of risk factors
  • any age
  • hyperacusis
  • dysgeusia
Other diagnostic factors

Risk factors

  • intranasal influenza vaccination
  • pregnancy
  • upper respiratory tract infection
  • arid/cold climate
  • hypertension
  • family history of Bell's palsy
  • diabetes
  • dental procedures
More risk factors

Diagnostic investigations

1st investigations to order

  • clinical diagnosis
  • electroneuronography (ENoG) (evoked electromyography - eEMG)
  • needle electromyography (EMG)
  • serology for Borrelia burgdorferi
More 1st investigations to order

Investigations to consider

  • pure-tone audiometry
  • tympanometry and stapedius reflex
  • MRI (gadolinium-enhanced fine-cut of facial nerve course)
  • CT (fine-cut, non-enhanced)
More investigations to consider

Treatment algorithm


all patients



Matthew Q. Miller, MD

Assistant Professor Otolaryngology-Head and Neck Surgery

Director UNC Facial Nerve Center

University of North Carolina-Chapel Hill

Chapel Hill



MQM declares that he has no competing interests.

Liliana Ein, MD

Assistant Professor Otolaryngology-Head and Neck Surgery

Division of Facial Plastic and Reconstructive Surgery

University of Miami




LE declares that she has no competing interests.


Dr Matthew Q. Miller and Dr Liliana Ein would like to gratefully acknowledge Dr Tessa Hadlock, Dr Nathan Jowett, Dr Vishnu Madhok, Dr Iain Swan, Dr Pauline Lockhart, Dr Michael Norbury, and Dr John Gail Neely, previous contributors to this topic.


TH, VM, IS, PL, MN, and JGN declare that they have no competing interests. NJ holds a patent on the methods and systems for functional electrical stimulation of the paralysed face (WO2017124019A1).

Peer reviewers

Giles Elrington, MBBS (Hons), MD, FRCP

Consultant Neurologist

Barts Health NHS Trust




GE is involved in a number of clinical trials on multiple sclerosis sponsored by Genzyme, Roche, Teva, Novartis, Biogen, as well as one funded by the MRC. He is also involved in clinical trials sponsored by Allergan, NMT Medical, GlaxoSmithKline (GSK), Bristol-Myers, the UK's Parkinson's Disease Research Group, and Pharmacia. In addition, he has attended lectures, conferences and symposia with the following companies - GSK, Astra Zeneca, MSD, Almirall, Pfizer, Menarini, Allergan, Biogen, Teva, Conference Plus, Infomed, BMJ.

Patrick Grogan, MD


US Air Force

MC Program Director

Department of Neurology


Wilford Hall Medical Center

Lackland Air Force Base



PG declares that he has no competing interests.

Venkat Srinivasan, MBBS, DLO, FRCS (Ed), FRCS (ORL)

Consultant in ENT/Thyroid Surgery

Arrowe Park Hospital





VS declares that he has no competing interests.

  • Differentials

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  • Guidelines

    • ACR appropriateness criteria: cranial neuropathy
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  • Patient leaflets

    Bell's palsy

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