Medically reviewed by Drugs.com. Last updated on Oct 11, 2019.
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 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.
In most cases, the exact cause of nerve inflammation in people with Bell's palsy is unclear. Researchers suspect the inflammation is most often triggered by a viral infection, such as herpes simplex, the same virus that causes cold sores (fever blisters). A variant of Bell's palsy, called Ramsay-Hunt syndrome, is caused by the herpes zoster virus, the virus that causes chickenpox and shingles. A less common cause of Bell's palsy is Lyme disease. People with diabetes are more likely to develop Bell's palsy.
Usually, 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.
Doctors usually can diagnose Bell's palsy based on a physical examination. Your doctor 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. These symptoms are not associated with Bell's palsy, but this will help to rule out other causes of facial weakness.
Your doctor will look for a shingles like rash on your face and ear. If you have this rash, especially if it is painful, your doctor will diagnose Ramsay-Hunt syndrome caused by reactivation of the herpes zoster virus.
If there are no other symptoms, and the only problem is weakness in facial muscles, your doctor can diagnose Bell's palsy without further testing. A blood sugar test may be ordered if you have not had one recently, because people with diabetes are more likely to get Bell's palsy. A blood test for Lyme disease also may be done.
Most people's symptoms peak at 48 hours, start to improve by 2 weeks, and they are back to normal by 6 months. In some cases, the symptoms do not go away completely and there is some permanent facial weakness.
There is no way to prevent Bell's palsy.
If the symptoms are very mild, treatment may not be necessary. Most commonly, people with Bell's palsy are prescribed prednisone (Deltasone, Orasone and others), a corticosteroid, to reduce the inflammation and swelling in the nerve. Some doctors prescribe a combination of prednisone and an anti-herpes virus drug, such as valacyclovir (Valtrex) for 7 days.
If the Bell's palsy is part of the Ramsay-Hunt syndrome, treatment should always include anti-herpes drug, usually valacyclovir, along with prednisone. Bell's palsy related to Lyme disease is treated with antibiotics active against the bacteria that cause Lyme disease.
If Bell's palsy is affecting your ability to close your eyes, your cornea can become dry and possibly get scratched. To prevent this, you must protect your eyes from wind and dust by wearing glasses. You will need to keep your eyes moist by using artificial tears frequently during the day and lubricating your eyes at night with a sterile eye ointment.
When To Call a Professional
Call your doctor immediately at the first sign of decreased strength in your face, difficulty eating or drinking, or a droopy eyelid. Also call your doctor if your ear suddenly hurts, especially if you see blisters around your ear or inside your ear canal.
If you have been diagnosed with Bell's palsy, call your doctor immediately if your eye starts hurting or feels irritated. Call if your arms or legs feel weak, your vision changes, you get dizzy, have trouble swallowing, or get a headache that keeps getting worse. Contact your doctor promptly if any symptoms get worse.
Although the symptoms of Bell's palsy are frightening, there's a good chance that the nerve will be able to work properly again. Eighty-five percent of people with Bell's palsy recover completely within a few months. Children almost always recover completely.
Taste returns before facial strength. If taste returns within five to seven days after symptoms began, it's more likely you will recover completely. It's also more likely you will recover completely if your facial muscles were not fully paralyzed at the most severe point of the illness.
Factors associated with a poorer outlook include a higher degree of impairment, a longer time before symptoms start to improve, advanced age, and severe pain in or around the ear. The prognosis for Ramsay-Hunt syndrome is not as good as the prognosis for Bell's palsy.
American Academy of Otolaryngology