What is the best course of treatment for a patient presenting to the emergency department with left-sided Bell's (Bell's palsy) of unknown cause?

Management of Left-Sided Bell's Palsy in the Emergency Department

Immediately prescribe oral corticosteroids (prednisolone 50 mg daily for 10 days OR prednisone 60 mg daily for 5 days followed by a 5-day taper) and initiate aggressive eye protection measures, as treatment within 72 hours significantly improves facial nerve recovery from 63.6% to 83% at 3 months. 1

Immediate Diagnostic Confirmation

Before initiating treatment, confirm this is Bell's palsy by excluding other causes through focused examination:

• Test forehead involvement - Bell's palsy affects the entire ipsilateral face including the forehead, distinguishing it from stroke which spares forehead function 1, 2
• Assess for stroke red flags - Look for limb weakness, speech difficulties, altered mental status, dizziness, dysphagia, diplopia, or other cranial nerve involvement, which indicate stroke rather than Bell's palsy 2
• Examine all other cranial nerves - Any involvement of CN V, VI, VIII, IX, X, XI, or XII excludes Bell's palsy and mandates urgent imaging for central pathology or skull base lesion 2
• Verify rapid onset - Symptoms must develop within 72 hours; progressive weakness beyond this timeframe requires immediate reassessment for alternative diagnoses 1
• Check for bilateral involvement - Bilateral facial weakness is rare in Bell's palsy and suggests Lyme disease, sarcoidosis, or Guillain-Barré syndrome 2

Do NOT order routine laboratory tests or imaging for typical Bell's palsy presentations, as these are not recommended and delay treatment 1

Immediate Pharmacologic Treatment

Corticosteroid Therapy (MANDATORY)

• Prednisolone 50 mg orally daily for 10 days (preferred regimen) 1
  • Alternative: Prednisone 60 mg orally daily for 5 days, then taper over 5 days 1
• Evidence supporting steroids: 94.4% recovery at 9 months with prednisolone versus 81.6% with placebo 1
• Critical timing: Must initiate within 72 hours of symptom onset; treatment beyond this window has no proven benefit 1

Antiviral Therapy (OPTIONAL)

• May add valacyclovir 1 g orally three times daily for 7 days OR acyclovir 400 mg orally five times daily for 10 days 1, 3
• Combination therapy shows 96.5% complete recovery versus 89.7% with steroids alone, though the added benefit is small 1
• NEVER prescribe antivirals alone - monotherapy is ineffective and delays appropriate corticosteroid treatment 1

Immediate Eye Protection (CRITICAL)

Implement comprehensive eye protection immediately to prevent permanent corneal damage:

Daytime Protection

• Lubricating ophthalmic drops every 1-2 hours while awake to prevent moisture loss 1
• Sunglasses outdoors to protect against wind, foreign particles, and irritants 1
• Moisture chambers using polyethylene covers for severe cases with complete inability to close the eye 1

Nighttime Protection

• Ophthalmic ointment at bedtime for sustained moisture retention (causes temporary vision blurring) 1
• Eye taping or patching with careful instruction on proper technique to avoid corneal abrasion 1

Urgent Ophthalmology Referral Needed If:

• Complete inability to close the eye 1
• Eye pain, vision changes, redness, discharge, foreign body sensation, or increasing irritation despite protection 1

Patient Education and Discharge Instructions

Expected Recovery Timeline

• 70% of patients with complete paralysis recover fully within 6 months 1
• 94% of patients with incomplete paralysis recover fully 1
• Most patients begin recovery within 2-3 weeks of symptom onset 1
• 30% may experience permanent facial weakness with muscle contractures 1

Warning Signs Requiring Immediate Return

• New or worsening neurologic symptoms (limb weakness, speech changes, mental status changes) 1
• Development of ocular symptoms (pain, vision changes, redness) 1
• Progressive weakness beyond the initial 72-hour period 1
• Bilateral facial weakness developing 2

Mandatory Follow-Up Schedule

• 1-2 weeks after onset: Assess recovery trajectory, reinforce eye protection, identify early complications 1
• 3 months after onset: Mandatory reassessment or specialist referral if incomplete facial recovery 1, 4
• Immediate referral at any point for new neurologic findings or ocular symptoms 1

Common Pitfalls to Avoid

• Delaying treatment beyond 72 hours eliminates the proven benefit of corticosteroids 1
• Prescribing antiviral monotherapy is ineffective and delays appropriate steroid treatment 1
• Failing to test forehead function can lead to misdiagnosis of stroke as Bell's palsy 1
• Inadequate eye protection instruction can result in permanent corneal damage, particularly with improper taping technique causing corneal abrasion 1
• Missing other cranial nerve involvement delays diagnosis of serious central pathology requiring urgent imaging 2
• Ordering routine imaging or labs for typical presentations wastes resources and delays treatment 1