A Frightening Symptom With a Time-Sensitive Treatment
Bell's palsy is the most common cause of acute peripheral facial nerve paralysis. It causes sudden one-sided facial weakness — drooping of the mouth, inability to close the eye, loss of the smile on one side. For patients, the experience is terrifying: most assume they're having a stroke.
The good news: Bell's palsy is usually self-limited, prompt treatment with steroids substantially improves outcomes, and most patients recover completely. The bad news: distinguishing Bell's palsy from stroke and other causes of facial weakness requires prompt evaluation. Don't assume it's Bell's palsy — get evaluated.
At Zimmer Medical Group, we evaluate facial weakness urgently because the diagnosis affects what happens next.
What Bell's Palsy Is
Bell's palsy involves dysfunction of the seventh cranial nerve (facial nerve), causing weakness of the facial muscles on one side. The cause is thought to involve viral inflammation and swelling of the nerve as it passes through a narrow bony canal — possibly triggered by reactivation of herpes simplex virus.
The Critical Distinction: Bell's Palsy vs. Stroke
This is the most important early decision. Both can cause sudden facial weakness, but key differences:
Bell's Palsy (Peripheral Facial Nerve)
- All facial muscles affected on one side — including forehead
- Cannot raise the eyebrow on the affected side
- Cannot fully close the eye on the affected side
- No arm or leg weakness
- No speech difficulty (slurred speech possible from facial weakness, but no language impairment)
- No vision changes
- No confusion or other neurologic findings
Stroke (Central Facial Weakness)
- Lower face affected, forehead spared — the patient can still wrinkle the forehead and raise the eyebrow
- Often associated with arm or leg weakness on the same side
- May have speech impairment, vision changes, confusion
- May have other neurologic deficits
The forehead-sparing in stroke versus forehead-involvement in Bell's palsy is the most important physical exam finding. The reason: each side of the upper face receives input from both sides of the brain, while the lower face receives input only from the opposite brain hemisphere.
Bottom line: any sudden facial weakness should be evaluated urgently. Don't try to determine the cause yourself. Call 911 or go to an emergency department for any new facial drooping.
Recognizing Bell's Palsy
Common features:
- Sudden onset, often noticed on awakening
- Maximum severity within 72 hours
- Inability to close the eye on the affected side
- Drooping of the mouth corner
- Drooling
- Difficulty eating and drinking on the affected side
- Inability to wrinkle the forehead on the affected side
- Sensitivity to sound (hyperacusis) on the affected side
- Reduced taste sensation on the front 2/3 of the tongue on the affected side
- Pain behind or in the ear (often precedes the weakness)
- Reduced tear production on the affected side
Bell's palsy is more common in pregnancy, in patients with diabetes, and in patients with certain other conditions.
What Else Could It Be
Other causes of acute facial weakness to consider:
- Stroke — the most important to exclude
- Lyme disease — can cause Bell's palsy-like presentation; consider in endemic areas or after tick exposure
- Herpes zoster (Ramsay Hunt syndrome) — facial weakness with vesicles in the ear canal or on the eardrum
- Tumor — gradual onset rather than acute
- Trauma
- Acoustic neuroma — usually slowly progressive
- Sarcoidosis
- Mononucleosis or other viral infections
- Diabetes-related cranial neuropathy
- Bell's palsy of pregnancy
Diagnostic Workup
For typical Bell's palsy in an otherwise healthy patient:
- Detailed history and physical exam
- Examination to confirm peripheral pattern (forehead involvement)
- Assessment for other neurologic deficits
- Examination of the ear canal and eardrum
- Sometimes basic labs (glucose, sometimes others)
- Lyme testing if endemic area or exposure history
Imaging (MRI) is generally not needed for typical Bell's palsy but considered when:
- Atypical features
- No improvement after several weeks
- Bilateral facial weakness
- Recurrent episodes
- Other cranial nerve involvement
- Slow progression
Treatment
Corticosteroids (Most Important)
The single most evidence-supported treatment:
- Prednisone 60–80 mg daily for 5 days, then taper over 5 days
- Best started within 72 hours of symptom onset
- Improves complete recovery rates by approximately 15 percent
- Reduces incidence of synkinesis (abnormal regrowth of nerve fibers causing involuntary facial movements)
- Generally well-tolerated for short courses
This is why prompt evaluation matters. Steroids started later may still help but are most effective in the first 72 hours.
Antiviral Therapy
- Less evidence than steroids
- May offer modest additional benefit in severe cases (House-Brackmann grade 4 or worse)
- Acyclovir or valacyclovir typically used
- Generally reserved for severe cases combined with steroids
Eye Protection (Critical)
Patients who can't close their eye fully are at risk for corneal damage:
- Artificial tears during the day
- Lubricating eye ointment at night
- Eye patch or moisture chamber at night
- Eye taping when sleeping
- Refer to ophthalmology if any eye irritation develops
Untreated eye exposure can cause corneal abrasion, ulceration, and vision loss.
Physical Therapy
Facial physical therapy and exercises may help during recovery — particularly in cases with slower or incomplete recovery.
Other Considerations
- Reassurance
- Address eating difficulties
- Mental health support — sudden facial paralysis is psychologically difficult
- Avoid forced facial exercises early (may worsen synkinesis)
Recovery and Prognosis
The natural history of Bell's palsy:
- 70–85 percent of patients recover completely
- Recovery typically begins within 3 weeks
- Most patients are substantially improved by 3 months
- Some patients have ongoing recovery up to a year
- Complete recovery is more likely with mild initial weakness
Possible Long-Term Sequelae
Some patients have residual deficits:
- Synkinesis — involuntary facial movements during voluntary movements (eye closing when smiling, etc.)
- Hemifacial spasm
- Crocodile tears (tearing while eating)
- Persistent weakness
These are more common with severe initial weakness or delayed treatment.
Recurrence and Bilateral Cases
- Bell's palsy can recur in roughly 7–10 percent of patients
- Bilateral facial weakness is unusual for typical Bell's palsy and warrants additional workup (Lyme disease, sarcoidosis, Guillain-Barré syndrome, others)
Special Considerations
Pregnancy
Bell's palsy is more common in the third trimester and early postpartum:
- Treatment with steroids is generally appropriate
- Outcomes similar to non-pregnant patients
- Coordinate with obstetric provider
Diabetes
- Patients with diabetes have increased risk
- May have somewhat slower recovery
- Monitor glucose more carefully when starting steroid
Children
- Less common than adults
- Often associated with viral infections, ear infections, or Lyme disease
- Consider Lyme testing
- Recovery generally excellent
When to See Your Doctor
Call 911 or go to an emergency department for:
- Any sudden facial drooping
- Any sudden weakness, numbness, or speech changes
- Sudden vision loss
These symptoms can mean stroke and time matters. Don't wait to schedule a clinic visit.
For follow-up Bell's palsy care or recurrent symptoms:
- Schedule appointment after initial diagnosis
- Eye protection concerns
- Slow recovery
- Recurrent episodes
- Persistent residual weakness
- Synkinesis or other late complications
The American Academy of Neurology guidelines provide additional clinical detail on Bell's palsy management.
Recent diagnosis of Bell's palsy or sudden facial weakness? Contact Zimmer Medical Group for evaluation and a coordinated treatment plan including steroid therapy, eye protection, and follow-up care.
