(Facial Paralysis · 7th Nerve Palsy · Seventh Nerve Palsy)
In this condition factsheet:
The Facts on Bell's Palsy
Bell's palsy is a sudden facial paralysis that usually strikes all or part of one side of the face. Men or women of any age can suffer Bell's palsy, but statistics suggest that people in their 40s are more likely to get it. Overall, your risk of experiencing Bell's palsy is 1 in 5,000 each year, or 1.7% over an average lifetime. Some people may have Bell's palsy more than once in their life.
Bell's palsy can be a frightening experience, appearing suddenly with symptoms that cause many people to think they're having a stroke. In reality, stroke symptoms are quite different, and Bell's palsy is a condition that usually clears up without treatment.
Causes of Bell's Palsy
The exact cause of Bell's palsy is unknown, but most researchers believe that a viral infection that causes swelling and inflammation of the facial nerve is the most likely cause. Although research has found that the herpes simplex 1 virus (the virus that causes cold sores) is present, in many cases a direct link to the virus has not been proven.
Some people are more prone to Bell's palsy than others. Your risk is higher if you:
- have a family history of Bell's palsy
- have the common cold
- have diabetes
- have influenza
- are pregnant (third trimester)
Symptoms and Complications of Bell's Palsy
Bell's palsy usually appears suddenly, often overnight. The primary symptom is weakness and paralysis on one side of the face. You may find that you can't make the same expressions as usual. Typically, you'll be unable to fully close one eye. Other possible symptoms include:
- altered sense of taste
- facial pain, or pain in or behind the ear (in fewer than 50% of cases)
- no tears in one eye
- sensitivity to noise on the affected side
- numbness or heaviness in the face
Stroke is associated with other symptoms such as a severe headache, severe dizziness, difficulty speaking, numbness or weakness in the arm or legs, and blurred vision. You may have some trouble talking if you have Bell's palsy, but it's purely muscular and is not caused by bleeding or a blood clot in the brain.
Usually, the symptoms appear at once. Occasionally, they worsen over a few days. Steady, progressive paralysis over several weeks is not a sign of Bell's palsy.
The most serious complication seen in Bell's palsy is permanent mild facial paralysis. This is found in a minority of cases. Overall, about 80% recover completely over weeks to months, and most of the rest improve.
Incomplete recovery is more likely in people who are older than 60 or those experiencing weakness or paralysis on both sides of the face - this occurs in 1% of cases. People who don't recover completely may be left with one or more of the following symptoms:
- abnormal blinking
- asymmetrical smile
- buccinator paralysis (food caught in cheek of paralyzed side)
- corneal damage
- drooling of liquids from the corner of paralyzed mouth
- dry eye
- frozen muscle in the nostril area
- hyperacusis (perceiving sounds as unusually loud)
- impaired taste
- impaired speech
- synkinesis (involuntary movement associated with a voluntary movement)