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For further information, see CMDT Part 24-32: Bell Palsy

Key Features

Essentials of Diagnosis

  • Sudden onset of lower motor neuron facial palsy

  • May have hyperacusis or impaired taste

  • No other neurologic abnormalities

General Considerations

  • Idiopathic lower motor neuron facial paresis

  • Attributed to an inflammatory reaction of the facial nerve near the stylomastoid foramen or in the bony facial canal

  • Reactivation of herpes simplex or varicella zoster virus has been postulated

  • Common in pregnancy or in diabetes mellitus

Clinical Findings

Symptoms and Signs

  • Generally comes on abruptly, but may worsen over 1 or 2 days

  • Pain about the ear often precedes or accompanies the weakness but usually lasts for only a few days

  • There may be ipsilateral restriction of eye closure and difficulty with eating and fine facial movements

  • A disturbance of taste is common, owing to involvement of chorda tympani fibers, and hyperacusis due to involvement of fibers to the stapedius occurs occasionally

  • Vesicles may be observed in the external ear canal in cases due to herpes zoster infection

Differential Diagnosis

  • HIV-related facial neuropathies

  • Lyme disease

  • Sarcoidosis

  • Ramsay Hunt syndrome (herpes zoster of geniculate ganglion)

  • Acoustic neuroma

  • Acute or chronic otitis media

  • Malignant otitis externa

  • Guillain-Barré syndrome

  • Tumor, eg, parotid, temporal bone tumor

  • Brainstem infarct


  • Clinical features are characteristic

  • Electromyography and nerve excitability or conduction studies provide a guide to prognosis

Laboratory Tests



  • Corticosteroids increase the chance of a complete recovery at 9–12 months by 12–15%

    • Prednisone 60 mg orally daily for 5 days followed by a 5-day taper or

    • Prednisolone 25 mg orally twice daily for 10 days

  • It is helpful to protect the eye with lubricating drops (or lubricating ointment at night) and a patch if eye closure is not possible

  • Acyclovir or valacyclovir is only indicated when there is evidence of herpetic vesicles in the external ear canal


  • There is no evidence that surgical procedures to decompress the facial nerve are of benefit

Therapeutic Procedures

  • The management is controversial

  • Approximately 60% of cases recover completely without treatment

  • Physical therapy may improve facial function



  • Patients with clinically complete palsy when first seen are less likely to make a full recovery than those with an incomplete one

  • A poor prognosis for recovery is also associated with advanced age, hyperacusis, and severe initial pain



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