Bell palsy is a sudden weakness of one side of the face caused by dysfunction of the facial nerve (cranial nerve VII) with no other cause found. Most patients recover within weeks to months, and early steroids improve the chance of full recovery.
Key symptoms
- One-sided facial droop that develops over hours to 3 days
- Trouble closing the eye; dry or watery eye
- Drooling and food trapped in the cheek
- Pain behind the ear, altered taste, sounds too loud
What you find on exam
- Weakness of the whole half of the face, including the forehead
- Forehead sparing suggests a stroke instead
- Normal exam of the other cranial nerves and the limbs
- Ear and parotid exam for vesicles or masses
- Eye closure and corneal protection
Tests
- Diagnosis is clinical in typical cases
- Lyme serology in endemic areas
- Glucose or HbA1c and blood pressure as risk factors
- MRI if atypical, recurrent or no improvement after 3 months
Treatment basics
- Oral prednisone within 72 hours of onset, for about 10 days
- Antiviral such as valacyclovir added to the steroid in severe cases
- Eye care: artificial tears by day, ointment and taping at night
- Follow-up; refer if not recovering after 3 months
Red flags
- Forehead sparing or other neurologic deficits (possible stroke)
- Vesicles in the ear or both sides of the face affected
- Eye that cannot close, with pain or redness (corneal injury)
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Sources: NCCPA PANCE Content Blueprint; NBOME COMLEX-USA clinical presentations; AAMC Core Entrustable Professional Activities (Core EPAs). Written by Making Synapses. Making Synapses is not affiliated with these organizations.