Bell’s Palsy: Definition, Causes, Symptoms & Treatment

Bell’s Palsy: Definition, Causes, Symptoms & Treatment

What is Bell’s palsy?

Bell’s palsy is a condition that causes temporary facial paralysis (palsy). It usually only affects the muscles on one side of your face. You may have a lopsided smile or an eyelid that you can’t fully close. It rarely affects both sides of your face.

Bell’s palsy happens when there’s inflammation and swelling of your seventh cranial nerve — the nerve that controls facial muscles. Certain conditions (like viral infections) can cause inflammation, but many cases of Bell’s palsy have no clear cause (idiopathic).

Bell’s palsy can affect anyone at any age. But it’s most likely to affect people between the ages of 15 and 60. The average age of onset is 40 years.

The condition gets its name from Sir Charles Bell, a Scottish surgeon who first described it during the 19th century.

Is Bell’s palsy a serious condition?

Bell’s palsy isn’t a serious condition. Most cases go away on their own with time. However, the symptoms of Bell’s palsy are similar to those of serious medical conditions, like a stroke. This is why it’s important to see a healthcare provider as soon as you notice muscle weakness in your face.

Signs of a stroke include:

  • One-sided weakness or paralysis.
  • Aphasia (difficulty with or loss of speaking ability).
  • Loss of muscle control on one side of your face.
  • Sudden loss — either partial or total — of one or more senses (vision, hearing, smell, taste and touch).
  • Blurred or double vision (diplopia).
  • Loss of coordination or clumsiness (ataxia).
  • Dizziness.
  • Nausea and vomiting.
  • Neck stiffness.
  • Emotional instability and personality changes.
  • Seizures.
  • Memory loss (amnesia).
  • Headaches (usually sudden and severe).

A stroke is a life-threatening emergency condition where every second counts. If you or someone with you has symptoms of a stroke, IMMEDIATELY call 911 (or your local emergency services number).

How common is Bell’s palsy?

Bell’s palsy is relatively common. About 15 to 30 people out of 100,000 develop it every year. About 1 in 60 people will get it at some point in their life. It’s the most common cause of one-sided facial paralysis.

Symptoms and Causes

What are the symptoms of Bell’s palsy?

The main sign of Bell’s palsy is facial muscle paralysis — usually on one side of your face. It looks like one side of your face is drooping. This includes your:

  • Forehead.
  • Eyebrow.
  • Eye and eyelid.
  • Corner of your mouth.

Symptoms of Bell’s palsy tend to come on suddenly and reach peak severity within 48 to 72 hours. Some people develop mild facial muscle weakness. Others experience total muscle paralysis in their face.

It’s difficult to make full expressions with Bell’s palsy. Wrinkling your forehead, blinking and grimacing may be difficult or impossible on the affected side. Your face may feel numb or heavy. But you can still feel touch and temperatures (like heat and coolness) on the affected side of your face.

Other symptoms of Bell’s palsy may include:

  • Drooling.
  • Dry eyes.
  • Difficulty speaking, eating or drinking.
  • Facial or ear pain.
  • Headache.
  • Loss of taste.
  • Ringing in your ears (tinnitus).
  • Sensitivity to sounds (hyperacusis).

Are there warning signs of Bell’s palsy?

Early symptoms of Bell’s palsy — or warning signs — may include a slight fever and pain behind your ear. However, there’s nothing you can do to stop Bell’s palsy from developing once it begins. In addition, you could have these symptoms for another reason and not develop Bell’s palsy.

What causes Bell’s palsy?

Inflammation and compression of your seventh cranial nerve is the main cause of Bell’s palsy.

The seventh cranial nerve carries nerve signals that control your facial movements and expressions. It also carries nerve signals involved in taste and producing tears in your eyes. You have two of these nerves — each controlling one side of your face. When one becomes inflamed, it affects how you can move the muscles on one side of your face.

Scientists have found that some viral infections may trigger inflammation of the seventh cranial nerve and cause Bell’s palsy. They include:

  • Herpes simplex 1 (a virus that causes mouth infections, like cold sores).
  • Varicella-zoster virus (chickenpox and shingles).
  • Epstein-Barr virus (mononucleosis).
  • COVID-19.

Other triggers may include having a weakened immune system from:

  • Stress.
  • Illnesses.
  • Sleep deprivation.
  • Physical trauma.
  • Autoimmune conditions.

Healthcare providers usually can’t find a specific trigger of Bell’s palsy.

What are the risk factors for Bell’s palsy?

Having the following may increase your risk of getting Bell’s palsy:

  • Diabetes.
  • Pregnancy.
  • Preeclampsia.
  • Obesity (BMI of 30 or higher).
  • High blood pressure (hypertension).
  • Having had Bell’s palsy before.

Diagnosis and Tests

How is Bell’s palsy diagnosed?

Your healthcare provider can diagnose Bell’s palsy based on your symptoms. They’ll ask about when your symptoms started and if they’ve changed. They’ll also do a physical exam and ask you to try to move your facial muscles in certain ways. The key physical exam finding of Bell’s palsy is partial or complete weakness of your forehead.

Other conditions, including stroke, sarcoidosis, Lyme disease, middle ear bacterial infections, multiple sclerosis and tumors near your facial nerve can sometimes cause facial paralysis that’s similar to Bell’s palsy. Your provider can usually accurately diagnose Bell’s palsy based on your history of symptoms and examination alone. But they may sometimes suggest that you have one or more of these tests:

  • Blood tests to check for conditions like Lyme disease or sarcoidosis.
  • Electromyography (EMG) to measure nerve activity and damage. This test may help your provider predict how quickly you’ll recover.
  • Magnetic resonance imaging (MRI) or computed tomography (CT) scans to rule out stroke, tumor, multiple sclerosis or other causes of nerve damage.
  • Lumbar puncture (spinal tap) to check for meningitis, Lyme disease or sarcoidosis.

Management and Treatment

How is Bell’s palsy treated?

Most cases of Bell’s palsy improve without treatment. Still, your healthcare provider may recommend one or more of these therapies for symptom relief and faster recovery:

  • Eye care: Eye drops, including artificial tears, soothe dry, irritated eyes. If your eyelid won’t close, you may need to wear an eye patch to protect that eye from drying, irritants and injuries. Eye care is very important to prevent damage to your cornea, a serious complication of Bell’s palsy.
  • Oral corticosteroids: Oral corticosteroids (like prednisone) can help decrease nerve swelling. It may help you regain facial movement faster. This treatment is most effective when you start it within 48 hours of noticing symptoms.
  • Antiviral medications: Antiviral medications may speed up recovery. But it’s unclear how much benefit they provide. Providers typically only prescribe them for severe Bell’s palsy. This treatment works best when you combine it with oral corticosteroids.
  • Electrical stimulation: Although some providers recommend electrical stimulation to prevent facial muscle loss after Bell’s palsy, studies haven’t shown any benefit of this treatment.

In the rare case that Bell’s palsy doesn’t go away, functional facial plastic surgery procedures are an option. They can help correct facial asymmetry and assist with eyelid closure.


How can I prevent Bell’s palsy?

Unfortunately, there’s nothing you can do to prevent Bell’s palsy. It’s linked to certain viral infections, but not everyone who has those viral infections develops Bell’s palsy.

If you have risk factors for the condition, like diabetes, obesity or high blood pressure, managing them well may help reduce your risk.

Outlook / Prognosis

How long does Bell’s palsy last?

Bell’s palsy can last a few weeks to six months. Symptoms usually start to gradually improve in three weeks. Up to 80% of people fully recover and show no signs of Bell’s palsy within three months.

Bell’s palsy can come back (recur) later in life. This happens to about 5% to 10% of people who’ve had it.

Is Bell’s palsy permanent?

Most cases of Bell’s palsy aren’t permanent. After some time, you’ll likely regain your full normal facial muscle function. This happens in about 80% of cases.

For others, facial weakness can be long-lasting. The longer the recovery, the more likely you’ll have lasting issues. The risk factors that are associated with poor outcomes include:

  • Complete facial paralysis.
  • Being over 60.
  • Having decreased salivation or taste.

Living With

When should I see my healthcare provider about Bell’s palsy?

If you have facial drooping, see a healthcare provider as soon as possible. Facial drooping is also a symptom of serious medical conditions, like a stroke. It’s better to know the cause right away.

Taking corticosteroids soon after symptoms of Bell’s palsy begin may also help speed up your recovery.

If you’ve received a diagnosis of Bell’s palsy, you should see your healthcare provider if you experience:

  • Symptoms that don’t improve within three months.
  • Chronic eye irritation.
  • An eyelid that won’t close.
  • Dehydration due to difficulty drinking and swallowing.
  • Hearing loss or dizziness/vertigo.

Takeaway Note

If you get Bell’s palsy, you may be embarrassed by how your face looks. The good news is that these symptoms usually improve with time. See your healthcare provider when you first get symptoms. Corticosteroid treatments can speed recovery if you start them within 48 hours of noticing symptoms. Your provider can also rule out other, more serious conditions that cause facial paralysis.


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