Bell's Palsy
Key points
- Bell's palsy is a weakness of the muscles on one side of the face caused by problems with a facial nerve.
- In most cases, symptoms of Bell's palsy begin gradually and peak in 48 hours.
- Your doctor usually will be able to diagnose Bell's palsy based on a physical examination.
- If the symptoms are mild, treatment may not be necessary.
What Is It?
Bell's palsy is a weakness of the muscles on one side of the face caused by problems with a facial nerve. The nerve becomes inflamed and swollen and stops functioning properly.
There are two facial nerves, one for the right side of the face and one for the left. Each facial nerve has several branches. The main branch controls most of the muscles on one side of the face, including the muscles that control facial expression and the muscles that close and open the eyes and the lips. Other smaller branches go to the tongue and ear.
The nerve inflammation of Bell's palsy usually is caused by a viral infection. Two types of herpes viruses, the one that causes cold sores (fever blisters) and the chickenpox virus, are believed to be likely causes. Bell's palsy is more likely to attack people who have the flu or a cold, as well as pregnant women and people with diabetes. A less common cause of Bell's palsy is Lyme disease.
Symptoms
In most cases, symptoms of Bell's palsy begin gradually and peak in 48 hours. Early symptoms include changed sensation in a portion of the face, pain in or around the ear, increased or decreased hearing and impaired taste. As the condition progresses, a person typically has trouble closing his or her mouth and eye on one side of the face, and may complain of being unable to hold food in the mouth. The eyes also may tear more or less than usual. Pain often diminishes, but it can intensify.
Diagnosis
Your doctor usually will be able to diagnose Bell's palsy based on a physical examination. He or she will test for weakness in the muscles of the face, paying special attention to your ability to close both eyes and hold them closed. He or she also will ask you to smile or whistle to look for a difference on the two sides of your face. Your doctor will ask whether you are having any symptoms of numbness or weakness in other body parts or difficulty walking, symptoms not associated with Bell's palsy.
If there are no other symptoms, and the problems are only in your face, then your doctor can diagnose Bell's palsy without further testing. A blood sugar test may be ordered if you have not had one recently. A blood test for Lyme disease also may be done.
Expected Duration
Most symptoms go away within weeks to months.
Prevention
There is no way to prevent Bell's palsy.
Treatment
Written and revised by
David Cohen, M.D.
Our doctors write and review articles for accuracy and keep them up to date.
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