Diseases & Conditions

Bell's palsy

You wake up one morning, and your face feels stiff and odd. When you look in a mirror, half your face appears to droop. You can only manage half a smile. And your eye is dripping tears and doesn't want to close. What in the world is going on?

For many people, the first guess would be a stroke. But if your muscle weakness or paralysis affects only your face, a more likely cause is Bell's palsy.

Each year, about 40,000 Americans develop Bell's palsy, a condition that occurs when the nerve that controls the facial muscles becomes swollen or compressed. The problem can occur at any age, but rarely affects people under the age of 15 or over the age of 60.

For most people, Bell's palsy symptoms begin to improve within a few weeks, with complete recovery within three to six months. Between 8 percent and 10 percent will experience a recurrence of the signs and symptoms, sometimes on the opposite side of the face. And a small number of people never recover and continue to have some signs and symptoms for life.

The nerve that controls your facial muscles passes through a narrow corridor of bone on its way to your face. If this nerve becomes inflamed and swollen — usually from infection with a virus — it gets pinched in this tight corridor. Pressure from the bone can damage the protective covering of the nerve and interfere with communication between the nerve and your facial muscles, resulting in weakness and paralysis.

The most common cause of Bell's palsy appears to be the herpes simplex virus, which also causes cold sores and genital herpes. Other viruses that have been linked to Bell's palsy include the virus that causes chickenpox and shingles (herpes zoster), the virus that causes mononucleosis (Epstein-Barr), and another virus in the same family (cytomegalovirus).

Most people with Bell's palsy recover completely within a few months, with or without medical treatment. But not all instances of facial paralysis or weakness are due to Bell's palsy. See your doctor if you experience facial weakness, drooping or paralysis to determine the underlying cause and severity of the illness.

Although a mild case of Bell's palsy normally disappears within a month, recovery from a case involving total paralysis varies. If the damage to your facial nerve is unusually severe, the fibers may be irreversibly damaged. Another complication can arise from misdirected regrowth of nerve fibers, which can result in involuntary contraction of certain muscles when you're trying to move others. For example, when you smile, the eye on the affected side may close.

If you can't close your eye, you'll need to keep the eye moist with hourly eyedrops during the day and an eye ointment at night. If the clear protective covering of the eye — called the cornea — becomes too dry, it can cause permanent vision loss. Your doctor may want you to wear glasses or goggles during the day and an eye patch at night to protect your eye from getting poked or scratched.