Overview
Bell's Palsy
Quick Reference
Critical Alerts
- Rule out stroke: Central facial weakness spares forehead (stroke); peripheral involves entire face (Bell's)
- Eye protection is essential: Prevent corneal damage from incomplete closure
- Steroids improve outcomes: Start within 72 hours of symptom onset
- Antivirals controversial: Consider adding if severe
- Consider Lyme disease in endemic areas: Treat appropriately
- Ramsay Hunt syndrome (zoster oticus): Vesicles in ear canal—add antivirals
Central vs Peripheral Facial Weakness
| Feature | Central (Stroke) | Peripheral (Bell's) |
|---|---|---|
| Forehead | SPARED (bilateral innervation) | INVOLVED |
| Lower face | Weak | Weak |
| Eye closure | Intact | Weak/incomplete |
| Additional deficits | Arm/leg weakness, speech | None |
Emergency Treatments
| Intervention | Details |
|---|---|
| Steroids | Prednisone 60-80 mg/day × 7 days (taper optional) |
| Eye protection | Artificial tears, lubricating ointment, tape/patch at night |
| Antivirals (optional) | Valacyclovir 1g TID × 7 days (consider if severe) |
| Ramsay Hunt | Valacyclovir + prednisone |
Definition
Overview
Bell's palsy is an acute, idiopathic, unilateral peripheral facial nerve (CN VII) paralysis. It is the most common cause of acute facial paralysis, affecting all age groups. While most patients recover fully, early treatment with corticosteroids improves outcomes. The key ED task is distinguishing peripheral (Bell's) from central (stroke) facial weakness.
Classification
By Etiology:
| Type | Cause |
|---|---|
| Idiopathic (Bell's palsy) | Most common |
| Ramsay Hunt syndrome | Herpes zoster reactivation (VZV) |
| Lyme disease | Borrelia burgdorferi (endemic areas) |
| Otitis media/Mastoiditis | Extension of infection |
| Trauma | Temporal bone fracture |
| Tumor | Parotid, cerebellopontine angle |
| Guillain-Barré syndrome | Bilateral facial weakness |
Epidemiology
- Incidence: 20-30 per 100,000/year
- Peak age: 15-45 years
- Equal gender: Slightly higher in pregnancy (3rd trimester)
- Recurrence: 5-15%
- Most recover: 80-90% complete recovery
Etiology
Proposed Mechanism:
- Herpes simplex virus (HSV-1) reactivation most commonly implicated
- Inflammation and edema of CN VII in facial canal
- Compression leads to demyelination and axonal damage
Risk Factors:
| Factor | Notes |
|---|---|
| Diabetes | Higher incidence |
| Pregnancy | 3rd trimester, postpartum |
| Immunocompromise | HSV, VZV reactivation |
| Recent viral URI | Preceding illness common |
Pathophysiology
Mechanism
- HSV-1 reactivation (or other trigger): Viral involvement of geniculate ganglion
- Inflammation: Edema of facial nerve within bony canal
- Compression: Facial canal is rigid
- Ischemia: Compromised vascular supply
- Demyelination/Axonal damage: Degree determines recovery
Anatomy of Facial Nerve (CN VII)
- Motor: Facial expression muscles
- Parasympathetic: Salivation (submandibular, sublingual), lacrimation
- Sensory: Taste anterior 2/3 tongue, sensation external ear
Clinical Presentation
Symptoms
| Symptom | Description |
|---|---|
| Acute onset facial weakness | Over hours to 1-3 days |
| Unilateral | Almost always |
| Forehead weakness | Inability to raise eyebrow |
| Eye closure weakness | Incomplete (Bell's phenomenon: eye rolls up) |
| Mouth droop | Inability to smile, drooling |
| Ear pain (retroauricular) | Prodrome or concurrent |
| Hyperacusis | Stapedius weakness → Sensitivity to loud sounds |
| Taste disturbance | Anterior 2/3 tongue |
| Dry eye | Decreased lacrimation |
History
Key Questions:
Physical Examination
Facial Nerve Assessment:
| Function | Test |
|---|---|
| Forehead | Raise eyebrows |
| Eye | Close eyes tightly |
| Mouth | Smile, puff cheeks, purse lips |
| Bell's phenomenon | Eye rolls upward with attempted closure (normal protective reflex) |
| Taste | (Not typically tested in ED) |
| Lacrimation | (Not typically tested in ED) |
Central vs Peripheral:
| Feature | Central (UMN) | Peripheral (LMN/Bell's) |
|---|---|---|
| Forehead | Spared | Affected |
| Eye closure | Intact | Affected |
| Lower face | Weak | Weak |
| Other deficits | Arm/leg weakness, dysarthria | None |
Other Exam:
| Finding | Significance |
|---|---|
| Vesicles in ear canal or TM | Ramsay Hunt syndrome (VZV) |
| Parotid mass | Tumor |
| Other cranial nerve deficits | Stroke, tumor, GBS |
| Mastoid tenderness | Mastoiditis |
Time of onset (sudden vs gradual)
Common presentation.
Associated symptoms (ear pain, vesicles, hearing loss)
Common presentation.
Weakness elsewhere (arms, legs, speech)
Common presentation.
Recent tick bite or travel (Lyme)
Common presentation.
Diabetes or pregnancy
Common presentation.
Prior episodes of facial weakness
Common presentation.
Immunocompromise
Common presentation.
Red Flags
Must Exclude Serious Causes
| Finding | Concern | Action |
|---|---|---|
| Forehead sparing | Central lesion (stroke) | Stroke workup |
| Arm/leg weakness | Stroke | Emergent CT/MRI |
| Bilateral facial weakness | GBS, Lyme, tumor | Workup |
| Gradual onset (> weeks) | Tumor | MRI |
| No improvement by 3-6 months | Tumor, incomplete recovery | MRI, ENT/Neurology |
| Vesicles in ear | Ramsay Hunt | Add antivirals |
| Multiple cranial nerve deficits | Brainstem lesion, carcinomatous meningitis | MRI |
Differential Diagnosis
Other Causes of Facial Weakness
| Diagnosis | Features |
|---|---|
| Stroke | Forehead spared, other deficits |
| Ramsay Hunt syndrome | VZV vesicles in ear, hearing loss |
| Lyme disease | Endemic area, tick bite, bilateral possible |
| Otitis media/Mastoiditis | Ear pain, fever, TM abnormality |
| Parotid tumor | Gradual, mass palpable |
| Acoustic neuroma | Hearing loss, CN VIII involvement |
| Guillain-Barré syndrome | Ascending weakness, bilateral facial |
| Sarcoidosis | Bilateral, systemic symptoms |
| Trauma | Temporal bone fracture |
Diagnostic Approach
Clinical Diagnosis
- Bell's palsy is a clinical diagnosis of exclusion
- Must differentiate from central causes (stroke)
Imaging
Not Routinely Required for Typical Bell's Palsy
Consider MRI if:
- Atypical presentation
- No improvement by 3-4 weeks
- Recurrent episodes
- Gradual onset
- Other neurological deficits
CT Head (If stroke suspected):
- Forehead sparing
- Other focal deficits
Laboratory Studies
Not Routinely Needed
Consider:
| Test | Indication |
|---|---|
| Lyme serology | Endemic area, bilateral, or rash/tick bite |
| Glucose | Diabetes screening |
| HIV | If immunocompromise suspected |
| ESR, ACE level | If sarcoidosis suspected |
Electrodiagnostic Testing
- Electroneuronography (ENoG) or EMG
- Used to assess prognosis
- Not performed in ED; refer if needed
Treatment
Principles
- Steroids within 72 hours: Improve recovery
- Eye protection: Prevent corneal damage
- Antivirals: Controversial; consider if severe
- Rule out other causes: Stroke, Lyme, VZV
- Reassurance: Most recover fully
Corticosteroids
Prednisone:
| Dose | Duration |
|---|---|
| 60-80 mg/day | 7 days (can taper or stop abruptly) |
Alternative: Methylprednisolone equivalent
Evidence: Strong evidence that steroids improve complete recovery rates
Contraindications: Relative (uncontrolled diabetes, active infection)—benefits usually outweigh risks
Antiviral Therapy
Controversial:
- Studies show mixed results
- May add modest benefit when combined with steroids
- Consider for severe cases (House-Brackmann grade IV-VI)
If Used:
| Agent | Dose | Duration |
|---|---|---|
| Valacyclovir | 1 g TID | 7 days |
| Acyclovir | 400 mg 5× daily | 7-10 days |
Ramsay Hunt Syndrome (Herpes Zoster Oticus)
Always treat with antivirals + steroids:
| Agent | Dose |
|---|---|
| Valacyclovir | 1 g TID × 7 days |
| + Prednisone | 60-80 mg/day × 7 days |
Prognosis is worse than Bell's palsy
Eye Care
Essential to Prevent Corneal Damage:
| Intervention | Details |
|---|---|
| Artificial tears | q1-2h during day |
| Lubricating ointment | At night |
| Eye patch/tape | At night to close lid |
| Moisture chamber or goggles | Alternative |
If incomplete eye closure: Ophthalmology referral
Lyme Disease-Associated Facial Palsy
If Lyme suspected or confirmed:
| Agent | Dose | Duration |
|---|---|---|
| Doxycycline | 100 mg BID | 14-21 days |
| OR Amoxicillin | 500 mg TID | 14-21 days |
Steroids not recommended for Lyme-associated facial palsy
Disposition
Discharge Criteria
- Typical Bell's palsy presentation
- No signs of stroke or other serious cause
- Eye protection education
- Steroids prescribed
- Follow-up arranged
Referral
| Indication | Referral |
|---|---|
| Incomplete eye closure | Ophthalmology |
| No improvement in 3-4 weeks | Neurology |
| Atypical features | Neurology, ENT |
| Ramsay Hunt | ENT |
Follow-Up
| Situation | Follow-Up |
|---|---|
| Typical Bell's | PCP or Neurology in 2-4 weeks |
| Severe or Ramsay Hunt | Neurology/ENT in 1-2 weeks |
| Eye involvement | Ophthalmology |
Patient Education
Condition Explanation
- "You have Bell's palsy, which is a temporary paralysis of the facial nerve."
- "We don't know exactly what causes it, but it may be related to a viral infection."
- "Most people recover completely within a few weeks to months."
- "Protecting your eye is very important since you can't blink properly."
Home Care
- Use artificial tears and ointment as directed
- Tape or patch eye closed at night
- Wear sunglasses outside
- Massage facial muscles gently
- Continue steroids as prescribed
Warning Signs to Return
- Weakness in arm or leg
- Difficulty speaking or understanding
- Severe headache
- Vision changes
- Eye pain or redness
- Weakness not improving after 3-4 weeks
Special Populations
Pregnancy
- Higher incidence (3rd trimester, postpartum)
- Steroids are generally safe
- Avoid high-dose steroids near delivery if possible
- Eye care is essential
Diabetes
- Higher incidence
- Steroids may worsen glucose control
- Benefits usually outweigh risks—monitor glucose
- May have worse prognosis
Children
- Less common
- Always consider Lyme disease
- Similar treatment (weight-based steroids)
- Good prognosis
Quality Metrics
Performance Indicators
| Metric | Target | Rationale |
|---|---|---|
| Forehead weakness documented | 100% | Differentiate central vs peripheral |
| Steroids started within 72h onset | >0% | Improves recovery |
| Eye protection education | 100% | Prevent corneal damage |
| Stroke excluded if forehead spared | 100% | Life-threatening mimic |
Documentation Requirements
- Laterality (unilateral)
- Forehead involvement (confirms peripheral)
- Eye closure assessment
- Time of symptom onset
- Treatment prescribed
- Eye care education provided
- Follow-up plan
Key Clinical Pearls
Diagnostic Pearls
- Forehead involved = Peripheral (Bell's): Forehead spared = Central (Stroke)
- Acute onset (hours to days): Typical for Bell's
- Vesicles in ear = Ramsay Hunt: Add antivirals
- Bilateral = Not Bell's: Think Lyme, GBS, sarcoidosis
- Gradual onset = Tumor: MRI needed
- Always check for other deficits: Rule out stroke
Treatment Pearls
- Steroids work: Start within 72 hours
- Antivirals controversial: Consider if severe
- Eye care is critical: Corneal damage is preventable
- Lyme disease = Antibiotics, not steroids
- Ramsay Hunt = Both antivirals AND steroids
- Most recover completely: Reassure patients
Disposition Pearls
- Most can be discharged: With steroids and eye care
- Follow-up in 2-4 weeks: For reassessment
- Ophthalmology if eye at risk: Incomplete closure
- Neurology if no improvement: By 3-4 weeks
- MRI if atypical: Gradual onset, recurrent, bilateral
References
- Gronseth GS, et al. Practice Parameter: Steroids and antivirals for Bell palsy. Neurology. 2012;79(22):2209-2213.
- Sullivan FM, et al. Early treatment with prednisolone or acyclovir in Bell's palsy. N Engl J Med. 2007;357(16):1598-1607.
- Gagyor I, et al. Antiviral treatment for Bell's palsy (idiopathic facial paralysis). Cochrane Database Syst Rev. 2019;9:CD001869.
- Baugh RF, et al. Clinical Practice Guideline: Bell's Palsy. Otolaryngol Head Neck Surg. 2013;149(3 Suppl):S1-S27.
- Peitersen E. Bell's palsy: the spontaneous course of 2,500 peripheral facial nerve palsies of different etiologies. Acta Otolaryngol Suppl. 2002;(549):4-30.
- Murakami S, et al. Bell palsy and herpes simplex virus. Ann Intern Med. 1996;124(1 Pt 1):27-30.
- American Academy of Neurology. Practice parameter: steroids and antivirals for Bell palsy. 2012.
- UpToDate. Bell's palsy: Treatment and prognosis. 2024.