What is the first‑line management of acute idiopathic unilateral lower motor neuron facial nerve palsy (Bell's palsy)?

First-Line Management of Bell's Palsy

Prescribe oral corticosteroids within 72 hours of symptom onset—prednisolone 50 mg daily for 10 days or prednisone 60 mg daily for 5 days followed by a 5-day taper—as this is the only proven effective treatment that significantly improves facial nerve recovery. 1

Immediate Assessment and Diagnosis

• Confirm the diagnosis through rapid onset of unilateral facial weakness involving the forehead (developing in <72 hours) without identifiable cause, ensuring no other cranial nerve involvement or central signs that would suggest stroke, tumor, or infection 1, 2

• Do NOT order routine laboratory tests or imaging for typical presentations, as this delays treatment without improving outcomes 1, 3

• Distinguish from stroke by documenting forehead involvement (peripheral lesion affects entire face including forehead, while central stroke spares forehead) and absence of limb weakness, speech difficulties, or other neurologic deficits 2

Corticosteroid Therapy (Cornerstone Treatment)

• Initiate prednisolone 50 mg orally once daily for 10 days OR prednisone 60 mg orally once daily for 5 days followed by 5-day taper (10 mg decrements) 1, 3

• Treatment MUST begin within 72 hours of symptom onset—initiating beyond this window provides no benefit 1, 3

• Evidence demonstrates 83% recovery at 3 months with prednisolone versus 63.6% with placebo, and 94.4% recovery at 9 months versus 81.6% with placebo 1

• For diabetic patients, corticosteroids remain strongly recommended despite temporary hyperglycemia risk—monitor capillary glucose every 2-4 hours during first few days and proactively adjust diabetes medications 1

Antiviral Therapy Considerations

• Never prescribe antiviral monotherapy—it is completely ineffective and delays appropriate corticosteroid treatment 1, 3

• May offer valacyclovir 1 g three times daily for 7 days OR acyclovir 400 mg five times daily for 10 days in combination with corticosteroids within 72 hours, though added benefit is minimal (96.5% complete recovery versus 89.7% with steroids alone) 1, 4

• The decision to add antivirals should acknowledge the small potential benefit against minimal risks 1

Eye Protection (Critical for Preventing Permanent Corneal Damage)

• Implement immediately for all patients with impaired eye closure: 1

  • Lubricating ophthalmic drops every 1-2 hours while awake
  • Ophthalmic ointment at bedtime for sustained moisture retention
  • Eye taping or patching at night with careful instruction on proper technique to avoid corneal abrasion
  • Sunglasses outdoors for protection against wind and foreign particles
  • Moisture chambers using polyethylene covers for severe cases

• Refer urgently to ophthalmology for severe impairment with complete inability to close the eye or any signs of corneal exposure (pain, redness, vision changes, foreign body sensation) 1

Therapies NOT Recommended

• Physical therapy has no proven benefit over spontaneous recovery and should not be used as primary treatment 1, 5

• Acupuncture is not recommended due to poor-quality evidence and indeterminate benefit-harm ratio 1

• Surgical decompression is contraindicated except in rare specialized circumstances 1

Follow-Up and Referral Triggers

• Schedule reassessment at 1-2 weeks to monitor recovery trajectory, reinforce eye protection, and identify early complications 1

• Mandatory referral to facial nerve specialist at 3 months if facial recovery remains incomplete 1, 3

• Immediate referral required for: 1

  • New or worsening neurologic findings at any point (suggests alternative diagnosis)
  • Development of ocular symptoms (corneal exposure risk)
  • Progressive weakness beyond 3 weeks (atypical for Bell's palsy)

Special Population Considerations

• Children: Have better prognosis with higher spontaneous recovery rates (up to 94%), but corticosteroid benefit is less conclusive—involve caregivers in shared decision-making regarding treatment 1, 3

• Pregnant women: Treat with oral corticosteroids within 72 hours using individualized risk-benefit assessment, as pregnancy increases Bell's palsy risk 1

Common Pitfalls to Avoid

• Delaying corticosteroid initiation beyond 72 hours eliminates treatment effectiveness 1, 3

• Prescribing antiviral monotherapy instead of corticosteroids wastes critical treatment window 1, 3

• Failing to provide adequate eye protection instructions leads to preventable corneal damage 1

• Missing atypical features (bilateral weakness, isolated branch paralysis, other cranial nerve involvement, gradual onset) that indicate alternative diagnoses requiring imaging 1, 2

• Ordering unnecessary laboratory tests or imaging for typical presentations delays treatment 1, 3