Bell's palsy: Symptoms, diagnosis and treatment

What is Bell's palsy?

Bell's palsy is a type of paralysis (or weakness) of the muscles in the face, thought to be due to inflammation of the seventh cranial nerve, also known as the facial nerve. While it can strike anyone, it seems to occur more frequently in individuals recovering from viral infections and people with diabetes. Bell's palsy affects only one side of the face at a time, and only rarely recurs in the same individual.

Bell's palsy tends to come on very suddenly. You may go to bed one night with no noticeable symptoms, only to look in the mirror the next morning and notice that your face appears to be drooping. Some people notice pain behind their ear a day or two before they notice any weakness. Others comment that sounds seem abnormally and uncomfortably loud several days before the development of paralysis. Within a day or two, the paralysis usually reaches its peak. Most people start to recover within a couple of weeks and are completely recovered within three months. Some people who develop Bell's palsy have a longer recovery period or have some permanent symptoms of the condition.

Many people with Bell's palsy worry that they are having a stroke. This is unlikely because a stroke that affects the face muscles would also cause muscle weakness in other parts of the body.

What causes Bell's palsy?

The exact cause of Bell's palsy has not been pinpointed. Most doctors assume that some process causes swelling of the facial nerve. Because the facial nerve passes through a narrow, bony area within the skull, any swelling of the nerve causes it to be compressed against the skull's hard, bony surface. This interferes with the nerve's functioning. Researchers have long believed that viral infections may be involved in the development of Bell's palsy. Scientists have found evidence suggesting that the herpes simplex 1 virus (a common cause of cold sores) may be responsible for a large percentage of Bell's palsy cases.

What are the symptoms of Bell's palsy?

The symptoms of Bell's palsy can include:

• Drooping of the muscles on one side of the face
• Inability to close the eyelid on the affected side and the inability to blink
• Excess or decreased tearing
• Drooling
• Difficulty chewing on the affected side
• Decreased sense of taste on the affected side
• Twitching of the muscles on the affected side
• Pain or numbness behind the ear on the affected side of the face
• Hyperacusis, an increase in sensitivity to noise on the affected side of the face

Seek medical advice about Bell's palsy if you have any of the following:

• Weakness or drooping of your facial muscles.
• You cannot blink or close your eye.
• You have excess or decreased tearing.
• You have numbness, pain or twitching of your facial muscles