Acute unilateral facial palsy of probable viral aetiology.
Clinical diagnosis of exclusion.
High-dose corticosteroids should be administered in all patients in the absence of significant contraindications.
Other treatment options include concomitant antiviral agents, physiotherapy, and, in severe cases, surgical decompression.
Eye protection should always be considered.
Failure to demonstrate any return of hemi-facial tone or movement within 4 to 6 months suggests an alternative diagnosis.
Bell's palsy is an acute unilateral peripheral facial nerve palsy in patients for whom physical examination and history are otherwise unremarkable, consisting of deficits affecting all facial zones equally that fully evolve within 72 hours. To date, it remains a clinical diagnosis of exclusion. Complete recovery to normal facial function occurs in approximately 70% of untreated cases, with permanently impaired facial function occurring to a minor degree in 13% and to a major degree in 16% of cases.  Onset of clinical recovery is nearly always demonstrated within 4 to 6 months of symptom onset; absence of any return of hemi-facial tone or movement by this time is highly suggestive of an alternative diagnosis. Facial palsy of an otherwise known aetiology (e.g., Lyme disease-associated facial palsy), or facial palsy that is progressive, waxing and waning, or affects facial zones in an uneven fashion, is not Bell's palsy.
Professor of Otology and Laryngology
Director, Division of Facial Plastic and Reconstructive Surgery and Director, Facial Nerve Center
President, Sir Charles Bell Society
Massachusetts Eye and Ear Infirmary and Harvard Medical School
TH declares that she has no competing interests.
Division of Facial Plastic and Reconstructive Surgery
Massachusetts Eye and Ear Infirmary
NJ declares that he has no competing interests.
Dr Tessa Hadlock and Dr Nathan Jowett would like to gratefully acknowledge Dr Vishnu Madhok, Dr Iain Swan, Dr Pauline Lockhart, Dr Michael Norbury, and Dr John Gail Neely, previous contributors to this monograph. VM, IS, PL, MN, and JGN declare that they have no competing interests.
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.
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.
Consultant in ENT/Thyroid Surgery
Arrowe Park Hospital
VS declares that he has no competing interests.
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