What are the causes and treatment options for Bell's palsy (Idiopathic Facial Paralysis)?

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From the Guidelines

Bell's Palsy should be treated primarily with oral corticosteroids like prednisone, which should be started within 72 hours of symptom onset to reduce inflammation and improve recovery, as supported by high-quality randomized controlled trials 1.

Causes of Bell's Palsy

The exact cause of Bell's Palsy remains unclear, but it is believed to be triggered by:

  • Viral infections, particularly herpes simplex virus
  • Immune disorders
  • Localized inflammation, which compresses the facial nerve (cranial nerve VII) within the narrow facial canal

Treatment of Bell's Palsy

The treatment of Bell's Palsy includes:

  • Oral corticosteroids like prednisone (typically 60-80mg daily for 7 days, then tapered) to reduce inflammation and improve recovery
  • Antiviral medications such as valacyclovir (1000mg three times daily for 7 days) may be added, especially if herpes virus infection is suspected
  • Eye protection is crucial, including:
    • Artificial tears during the day
    • Lubricating eye ointment at night
    • Taping the eye closed if necessary to prevent corneal damage

Additional Considerations

  • Physical therapy with facial exercises and massage may help maintain muscle tone during recovery
  • Seek immediate medical attention for sudden facial weakness to rule out stroke and begin appropriate treatment promptly
  • Most patients (about 85%) recover completely within 3 months, though some may have residual weakness 1

From the Research

Causes of Bell's Palsy

  • The exact cause of Bell's palsy is unknown, but it is believed to be related to a reactivation of a latent microorganism such as herpes simplex type I 2
  • It is characterized by an acute onset of unilateral, lower motor neuron weakness of the facial nerve in the absence of an identifiable cause 3
  • Bell's palsy is idiopathic, meaning that it occurs without a known cause 4

Symptoms of Bell's Palsy

  • Acute onset of unilateral facial weakness or paralysis involving the forehead 4
  • May involve the entire face, including the forehead, eyelid, and mouth
  • Can cause difficulty with facial expressions, eye closure, and speech

Treatment of Bell's Palsy

  • Corticosteroids are the mainstay of treatment and should be initiated within 72 hours of symptom onset 3, 4
  • Antiviral therapy in combination with corticosteroid therapy may confer a small benefit and may be offered on the basis of shared decision making 3, 4
  • Recommended antivirals include valacyclovir or acyclovir 4
  • Treatment with antivirals alone is ineffective and not recommended 4
  • Physical therapy may be beneficial in patients with more severe paralysis 4

Treatment Outcomes

  • More than two-thirds of patients with typical Bell's palsy have a complete spontaneous recovery 4
  • For children and pregnant women, the rate of complete recovery is up to 90% 4
  • Treatment with valacyclovir and prednisone has been shown to be effective in improving recovery rates 2, 5
  • Steroid monotherapy remains effective, although combined treatment may have potential advantages, especially in patients with more severe disease 6

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Outcome of treatment with valacyclovir and prednisone in patients with Bell's palsy.

The Annals of otology, rhinology, and laryngology, 2003

Research

A general practice approach to Bell's palsy.

Australian family physician, 2016

Research

Bell Palsy: Rapid Evidence Review.

American family physician, 2023

Research

Valacyclovir and prednisolone treatment for Bell's palsy: a multicenter, randomized, placebo-controlled study.

Otology & neurotology : official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology, 2007

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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