Bell’s Palsy

Medically Reviewed by Brunilda Nazario, MD on July 31, 2020

What Is Bell's Palsy?

Bell's palsy is also known as “acute facial palsy of unknown cause.” It’s a condition in which the muscles on one side of your face become weak or paralyzed. It affects only one side of the face at a time, causing it to droop or become stiff on that side.

It’s caused by some kind of trauma to the seventh cranial nerve. This is also called the “facial nerve.” Bell’s palsy can happen to anyone. But it seems to occur more often in people who have diabetes or are recovering from viral infections.

Most of the time, symptoms are only temporary.

Bell’s Palsy Symptoms

If it happens to you, you may fear you’re having a stroke. You’re probably not. A stroke that affects your facial muscles would cause muscle weakness in other parts of your body, too.

Symptoms of Bell's palsy come on suddenly. Once they happen, they get worse over the next 48 to 72 hours.

The most noticeable sign is weakness and drooping on one side of your face. You’ll find it hard to close your eye on that side or make facial expressions like smiling. Your face may even be completely paralyzed on that side. It’s rare, but Bell’s palsy can sometimes affect the nerves in both sides of your face.

Besides the weakness and drooping of facial muscles, you may:

  • Drool
  • Feel pain in your jaw or behind your ear on the side that’s affected
  • Have a headache
  • Have less sense of taste
  • Have dry eyes and mouth
  • Hear ringing in your ears (tinnitus)
  • Be more sensitive to sound on the side that’s affected
  • Find it hard to talk
  • Have trouble eating and drinking

Once they happen, symptoms usually get better over the next 3 weeks or so. Most people -- up to 80% -- have no symptoms at all within 3 to 6 months.

Bell’s Palsy Causes

Most doctors believe that it’s due to damage to the facial nerve, which causes swelling. This nerve passes through a narrow, bony area within the skull. When the nerve swells -- even a little bit -- it pushes against the skull's hard surface. This affects how well the nerve works.

Researchers have long believed that viral infections may also play a role in the development of Bell's palsy. They’ve found evidence that suggests the herpes simplex 1 virus (a common cause of cold sores) may be responsible for a large number of cases. Other viruses that have a link to Bell’s palsy include:

Who Does Bell’s Palsy Affect?

Bell’s palsy most often happens in people between 15 and 60 years of age. It’s equally likely to affect men and women. But you may be more likely to get it if you’re pregnant, especially during the last 3 months or in the first week after you’ve given birth. You also have a greater chance of it if you have:

Bell’s Palsy Diagnosis

There’s no lab test for Bell’s palsy. Your doctor will examine your face and ask you to make different facial expressions to see how your muscles act. This is usually enough for them to make the diagnosis.

If there’s a chance that another condition is at play, your doctor may order an electromyography (EMG) test to measure the electrical activity inside the muscles. This can tell them if the nerves are definitely damaged and if so, how much.

Your doctor may also run an imaging test, such as an MRI or a CT scan, to make sure something like a tumor or bone fracture isn’t pressing on your nerves. A blood test can also help rule out diabetes or an infection.

Bell’s Palsy Treatment

Most people with this condition make a full recovery whether they get treatment or not. But there are some treatments that may help you heal faster.

Corticosteroids such as prednisone can help ease swelling and make it more likely that your nerve function will get back to normal. They work best if you take if you take them within 72 hours of the start of your symptoms. Taking an antiviral medication like acyclovir and valacyclovir along with the steroids may help restore function, but there isn’t definite proof of this.

If your palsy affects your ability to blink and close your affected eye, you’ll need to protect it. Use eye drops or an ointment to keep it moist. Wear an eye patch to keep dirt and dust out and moisture in.

Surgery isn’t recommended as a treatment option for Bell’s palsy.

WebMD Medical Reference



National Institute of Neurological Disorders and Stroke: “What Is Bell’s Palsy?” “Bell's Palsy Fact Sheet.” “What Is Bell’s Palsy?”

Mayo Clinic: “Bell’s Palsy.”

Cleveland Clinic: “Bell’s Palsy.”

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