Ask the doctors: Bell’s palsy causes sudden facial paralysis

Dear Doctors: A few weeks ago, one side of my dad’s face became paralyzed. He couldn’t close his left eye, and the left side of his mouth wouldn’t work. We thought it was a stroke, but the ER doctors said it is Bell’s palsy. They said it eventually goes away. What causes it? How long does it last?

Dear Reader: Bell’s palsy is a neurological disorder that occurs when something interrupts the signals from the facial nerve, which animates the muscles in the face. Known as cranial nerve VII, it also plays a role in taste and sensations in the ear. As happened with your father, this condition appears suddenly, can progress rapidly and usually affects just one side of the face. For that reason, it is sometimes mistaken as the effects of a stroke. It is possible, but rare, for Bell’s palsy to affect both sides of the face.

Symptoms include sudden weakness, or even paralysis, of the facial muscles. This causes the eyebrow and mouth to droop and the cheek to sag. The individual may be unable to close the eyelid on the affected side, which can cause excessive tearing. The sense of taste can be affected, and the lack of motor control of the muscles of the mouth may lead to drooling. Some people develop unusual sensations in the face and can become sensitive to loud sounds. Episodes of Bell’s palsy can last from a few weeks to six months or more. It is possible, but not common, for the effects to become permanent.

There is no specific test for Bell’s palsy. Diagnosis begins with a physical exam and medical history. It also includes tests, including blood tests and imaging scans, to rule out other possible causes of facial paralysis. These can include physical trauma, stroke, autoimmune disease or adverse drug reactions or interactions.

Bell’s palsy is the most common cause of facial paralysis. Although the exact cause of the disorder remains unclear, there appears to be a link to the functioning of the immune system. Risk factors include high blood pressure, diabetes, pregnancy, being overweight, having a dormant viral infection, autoimmune syndromes and living with an upper-respiratory ailment. Some researchers suspect chronic inflammation, which can damage the tissues that insulate the facial nerve, may also play a role.

It has been found that starting treatment with steroids within the first three days of the onset of the symptoms of Bell’s palsy can reduce inflammation, and perhaps speed the return of nerve function. When steroids are not an option, antiviral medications may have a similar positive effect. It is equally important for treatment plans to address each person’s specific symptoms. This includes the use of lubricating eye drops or an ointment to keep the surface of the affected eye moist. An eye patch will protect the eye, particularly the cornea, from debris and possible injury. If needed, analgesic medications may be prescribed for pain. Some patients find physical therapy, facial massage or alternative therapies such as acupuncture can help manage discomfort and ease symptoms.

Send your questions to askthedoctors@mednet.ucla.edu.