Bell’s Palsy

Medically Reviewed by Zilpah Sheikh, MD on November 14, 2023
7 min read

Bell's palsy is also known as “acute facial palsy of unknown cause.” It’s a condition in which the muscles in your face become weakened or paralyzed. It usually affects only one side of your face, causing it to droop or suddenly become stiff. Most of the time, the symptoms are only temporary.

Doctors don't know what causes it but think it may result from some kind of trauma to the seventh cranial nerve, which controls your facial muscles.

Who gets Bell’s palsy?

Though Bell’s palsy can happen to anyone, it mostly affects people aged 15-60 years. It affects men and women equally. 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 having it if you have:

  • Diabetes
  • A respiratory infection, such as a cold or the flu
  • An autoimmune disease
  • Cold sores
  • High blood pressure
  • Mononucleosis
  • Shingles
  • Obesity
  • Preeclampsia, a type of high blood pressure that happens during pregnancy

How common is Bell’s palsy?

Bell’s palsy is the most common reason people get one-sided facial paralysis. It affects about 40,000 people in the U.S. every year. About 1 out of every 60 people will get it at some point during their life.

Bell’s palsy triggers

Conditions that may trigger Bell’s palsy include:

  • A viral infection, such as HIV/AIDS, Lyme disease, or middle ear infection
  • Weakened immunity due to stress, lack of sleep, serious injury, or minor illness
  • Facial nerve infection and inflammation
  • Damage to the fatty covering that insulates your nerve fibers

Bell’s palsy vs. stroke

If you have symptoms of Bell's palsy, you might be afraid you’re having a stroke. Both can cause single-sided facial paralysis and have similar symptoms, such as trouble closing your eye or drooping on one side of your face. But there are significant differences.

For example, if the eye on your paralyzed side is watering or you have sensitive hearing or ringing in your ear, it's likely Bell's palsy. Changes in your sense of taste are also signs of Bell’s palsy.

But if you feel numbness or weakness in your arms or legs on one side of your body, it could be a stroke. With Bell’s palsy, you shouldn’t feel weak or have trouble moving your tongue.

Whatever symptoms you're having, if you suddenly have trouble moving one side of your face, get medical attention right away.



Symptoms of Bell's palsy come on suddenly. You may go to bed one night feeling fine and wake up the next morning with one side of your face weak or drooping.

You might 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 on both sides of your face.

Besides the weakness and drooping of your facial muscles, other symptoms of Bell's palsy may include:

  • Drooling
  • Pain in your jaw or behind your ear
  • Headache
  • Less sense of taste
  • Dry eye and mouth
  • Ringing in your ears (tinnitus)
  • Low tolerance for loud sounds
  • Difficulty talking
  • Trouble eating and drinking
  • Difficulty closing your eye
  • Problems smiling
  • Facial twitches

Most doctors think that Bell's palsy is caused by damage to the facial nerve, which causes swelling. This nerve passes through a narrow, bony area in your skull. When the nerve swells -- even a little bit -- it pushes against your skull's hard surface, which affects how well the nerve works.

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

  • Adenovirus (respiratory conditions)
  • Coxsackievirus (hand-foot-mouth disease)
  • Cytomegalovirus
  • Epstein-Barr (infectious mononucleosis)
  • Herpes zoster (chickenpox and shingles)
  • Influenza B (flu)
  • Lyme disease
  • Middle ear infection
  • Mumps
  • Rubella (German measles)

There’s no lab test for Bell’s palsy. Instead, your doctor will do a complete physical exam. They’ll examine your face and ask you to make different facial expressions to see how your muscles act. Most doctors can diagnose it based on your symptoms, but they'll also rule out other conditions such as stroke, middle ear infection, Lyme disease, and tumors.

To check for other health problems that can cause facial paralysis, your doctor might order tests including:

  • Blood tests to rule out other infections
  • Electromyography (EMG) to check your nerve activity and see if your paralysis will get better and how fast
  • Magnetic resonance imaging (MRI) or computed tomography (CT) scans to eliminate other problems that can cause paralysis

Is having Bell's palsy serious?

If you have Bell’s palsy, it usually isn’t serious. Your paralysis should go away in a few weeks or months without any treatment. But if you feel facial weakness or paralysis, it’s important to see a doctor right away to rule out more serious medical conditions.


If you have Bell's palsy, you're likely to make a full recovery even if you don't get treatment. But there are some things that may help you heal faster.

  • Corticosteroids (such as prednisone). These can help ease swelling of your facial nerve and help it start working normally faster. Corticosteroids work best if you take them soon after the start of your symptoms.
  • Antiviral drugs. Antiviral medications such as acyclovir (Sitavig, Zovirax) and valacyclovir (Valtrex) are sometimes prescribed in combination with corticosteroids, typically in severe cases of Bell's palsy. They don't seem to have much effect when they're taken alone.
  • Eye drops. If your Bell's palsy affects your ability to blink and close your eye, use eye drops or an ointment to keep it moist. Wear an eye patch to keep dirt and dust out and moisture in.
  • Surgery. Surgery is usually a last resort if your symptoms don’t go away, or if you have complications.

Bell’s palsy physical therapy

Even temporary paralysis can shrink and shorten your muscles. Physical therapy may help strengthen your facial muscles and help you get back facial coordination. You can also try massaging your face with your fingertips or exercising your facial muscles. Try to move every part of your face gently and slowly, using your fingers to help.

Is Bell’s palsy permanent?

While most people with Bell’s palsy completely recover, sometimes the symptoms are permanent. This may be the case if you still feel numbness or weakness on one side of your face after 6-12 months.

Your doctor can test to see if your facial nerves are showing signs of healing. If not, they may recommend cosmetic procedures to help you close your eye or fix a crooked smile. Or they may suggest surgery to help restore your facial muscles. These procedures may include nerve grafts to connect paralyzed facial muscles to healthy nerve tissue or moving healthy muscles from one part of your face to the paralyzed corner of your mouth.

How long does Bell's palsy last?

Once your symptoms start, they usually get worse over the next 48-72 hours. But, over the next few weeks, you should begin to see improvements in both the feeling and movement in your face. After 3 months, you'll probably be able to move your face like normal again.

Sometimes, however, the facial nerves don't heal correctly, and you may have long-term effects, such as:

  • Lopsided face
  • Crooked smile
  • Involuntary facial movements, such as closing an eye when you smile
  • Tightness of facial or neck muscles
  • Narrowing of eyes
  • Smile lines
  • Chin dimpling
  • Sagging skin around your neck

Bell’s palsy recovery signs

Because your symptoms can last for weeks or months, you may get frustrated or worried that you might not get better. It takes time for damaged nerve fibers to repair themselves.

The first signs that you're healing are usually evident in your muscle tone. You may notice the droopy side of your face looking less droopy. Next, your facial movements should start to return to normal.

Remember, most people recover fully from Bell's palsy in time.



Bell's palsy is when you suddenly have weak or paralyzed muscles on one side of your face. It usually causes a drooping mouth, eyebrow, and eyelid. But it's not serious and usually clears up without any type of treatment in a few months.

How contagious is Bell's palsy?

Bell’s palsy isn’t contagious. However, researchers think some types of viral infections might trigger Bell's palsy, and those infections can be contagious.

What is the main cause of Bell's palsy?

The main cause of Bell’s palsy is thought to be swelling of your seventh cranial nerve, which is the nerve that controls your facial muscles.