How common is weakness on one side in Bell's palsy?

Bell's palsy affects the facial nerve. Weakness can make one side of the face droop, make smiling uneven, or make it difficult to close one eye. Some people notice altered taste, sensitivity to sound or discomfort around the ear. The weakness is generally facial rather than affecting an arm or leg.

One-sided facial weakness has other possible causes, including stroke. The pattern, timing and accompanying symptoms help clinicians distinguish them. A new facial change should be assessed promptly, especially when it began suddenly.

Arrange urgent medical assessment for new facial weakness, because treatment for Bell's palsy may be time-sensitive and other causes need to be excluded. Protect an eye that does not close fully with the care advised by a clinician; dryness can injure the surface of the eye. Avoid putting unprescribed drops or ointments into the eye.

Note the exact time the weakness began and whether the forehead, speech, arm or leg are affected. Take a list of medicines and relevant medical conditions with you.

Call emergency services immediately for facial weakness with arm or leg weakness, trouble speaking, confusion, severe headache, loss of balance, vision change or difficulty swallowing. These symptoms can signal a stroke and need emergency assessment, even if they improve. Do not wait for facial symptoms to settle before seeking help.

Ask whether the weakness involves only the facial nerve, how to protect the eye, which treatment is appropriate, when follow-up should occur, and what changes would require emergency help.