Bell's palsy is a condition that affects the nerves in the face and results in weakness of the muscles in the face. Facial nerves carry electrical messages from the brain to the face that tell the muscles to move and help with actions like blinking or smiling. The exact cause of Bell’s palsy is not known, but it usually happens in response to a viral infection, such as the herpes virus or Epstein-Barr virus. The infection causes the facial nerves to swell and become pinched, which stops the messages from being sent correctly to one side of the face. In rare cases, both sides of the face can be affected.
Symptoms of Bell’s palsy develop quickly. In some cases, the affected person wakes up to find they have complete loss of facial muscles (paralysis) while other affected people do not have paralysis until several days after the first symptoms. Symptoms may include difficulty with closing one eye all the way, a droopy appearance to the face, difficulty making facial expressions, dryness in one eye, trouble tasting at the front of the tongue on the affected side, changes in the amount of saliva or drooling, and sensitivity to sound on the affected side. Risk factors for Bell’s palsy include age (older people are more likely to have Bell’s palsy), having a weakened immune system, and pregnancy. Trauma to the face or skull may also cause Bell’s palsy.
There is no specific test for Bell’s palsy. A doctor will typically rule out more severe causes of facial weakness, such as a tumor or stroke, by ordering a test to measure nerve function (electromyography (EMG)) or imaging exams (MRI or CT scan). Most affected individuals recover in a few weeks while only a small amount of people will have symptoms for life. Treatment options include medications, therapy, and surgery. If you have been diagnosed with Bell’s palsy, talk to a doctor about the most current treatment options.