Bell's Palsy

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What is Bell’s palsy?

Bell’s palsy is a temporary nerve disorder that affects the muscles on one side of the face. It happens when the facial nerve—7th cranial nerve—becomes inflamed and swollen. The facial nerve controls the facial muscles, tear ducts, saliva glands, and the sensation of taste. It gets its name from Dr. Charles Bell who described the involvement of the facial nerve in the 19th century.

Bell’s palsy causes muscle weakness, which usually affects one side of the face. This results in drooping on one side of the face. People with Bell’s palsy commonly have a lopsided smile and difficulty closing their eyelids properly. Other Bell’s palsy symptoms can include facial pain, excessive tearing, and altered or lack of sense of taste.

Typically, symptoms appear rather quickly, over 2 to 3 days. They improve gradually over the course of several weeks, regardless of whether you treat it or not. Most people recover within six months. However, Bell’s palsy can persist and become permanent in a small number of people.

The exact cause of Bell’s palsy is unclear. It commonly occurs in conjunction with a viral infection. Many scientists believe a dormant infection, such as Epstein-Barr virus or herpes viruses, is responsible. A trigger, such as stress or autoimmune reaction, may impair immunity and activate Bell’s palsy. It may also have a genetic component.

About 40,000 Americans suffer with Bell’s palsy each year. It most commonly affects people between the ages of 15 and 45 years. Your risk increases if you have a viral infection or diabetes. Pregnant and postpartum women also have a higher risk.

Most people will recover fully without treatment. However, treatment can ease your symptoms and speed recovery. The main Bell’s palsy treatment is corticosteroid drugs to reduce swelling and inflammation. Physical therapy can also help. Sometimes, doctors prescribe antiviral medicines, even though research is inconclusive about their effectiveness. When facial muscle problems persist, plastic surgery may help correct facial appearance.

Bell’s palsy itself is not life threatening and is rarely serious. However, Bell’s palsy symptoms can be very similar to stroke. Any time you experience facial weakness, especially on one side, you should seek immediate medical care (call 911). It is vital to rule out potentially serious or fatal conditions, including stroke, brain tumors, and Lyme disease.

What are the symptoms of Bell’s palsy?

Bell’s palsy symptoms develop suddenly, usually over hours to days. They most often affect one side of the face, but can affect both sides in rare cases.

Common symptoms of Bell’s palsy

The facial nerve is responsible for many functions and sensations. As a result, Bell’s palsy symptoms can include a variety of problems and vary from person to person. They can also vary in severity from mild to severe. The most common symptom of Bell’s palsy is facial weakness or paralysis. This can cause facial droop that is especially noticeable in the eyelids and mouth. Facial expressions are often affected. It may be difficult to close the eye properly and the smile may be lopsided.

Other common Bell’s palsy symptoms include:

  • Dry eye due to problems closing the eyelids all the way
  • Excessive tearing or drooling
  • Increased sensitivity to sound or ringing in the ear
  • Problems eating, drinking or speaking
  • Twitching

Serious symptoms that might indicate a life-threatening condition

Bell’s palsy is rarely serious and is not life threatening. However, Bell’s palsy symptoms can mimic stroke. Seek immediate medical care (call 911) if you, or someone you are with, have facial weakness or paralysis because it could be a sign of a stroke. With stroke, time is of the essence, so do not hesitate to seek medical care.

There are other conditions that also share the symptoms of Bell’s palsy. This includes brain tumors, myasthenia gravis, and Lyme disease. Doctors rule out other possible causes to diagnose Bell’s palsy.

What causes Bell’s palsy?

It is unclear exactly what causes Bell’s palsy. Several theories exist, but one of the main ones is a viral infection. Most scientists believe it results from a dormant viral infection that reactivates. Possible triggers include stress, sleep deprivation, trauma, and autoimmune reactions. The reactivation causes swelling and inflammation of the facial nerve, which causes the symptoms.

Doctors have linked several viruses to Bell’s palsy including:

  • Coxsackievirus
  • Epstein-Barr
  • Respiratory viruses, including cold and flu viruses
What are the risk factors for Bell’s palsy?

People of all ages and both sexes can get Bell’s palsy. However, it is most common in people between the ages of 15 and 45 years. There may also be a genetic link with Bell’s palsy. People with a family history may be more likely to develop it and possibly have a recurrence. Other possible risk factors for Bell’s palsy include:

  • Diabetes
  • Pregnancy, especially in the third trimester and the first week postpartum

Reducing your risk of Bell’s palsy

Currently, it isn’t possible to prevent Bell’s palsy or reduce your risk of getting it. See a doctor immediately if you develop symptoms of Bell’s palsy. It’s important to rule out other causes and treatment is more effective when you start it early.

How is Bell’s palsy treated?

Most people with Bell’s palsy fully recover with or without treatment. Mild cases may clear up gradually in about a month. But it can take up to six months to fully recover. Treatment can help relieve symptoms and may speed recovery. Your doctor may recommend the following Bell’s palsy treatment options:

  • Corticosteroids, such as prednisone, to reduce swelling and inflammation of the facial nerve. These drugs are most effective when you start them early, within a few days of symptom onset. This is the main treatment for Bell’s palsy.
  • Antivirals, such as acyclovir (Zovirax) and valacyclovir (Valtrex), may help and sometimes doctors prescribe them. However, research is inconclusive about their effectiveness in treating Bell’s palsy.
  • Physical therapy can help prevent permanent muscle contractures through massage and facial exercises.
  • Protecting the ocular surface. The clear cornea of the eye becomes vulnerable to injury and infection because the eyelids cannot fully close. Without the normal blink reflex the tear film evaporates. Topical lubricants, ointments, and temporary eyelid closure may be necessary to protect the eye until the Bell’s palsy resolves.

For pain, your doctor may recommend an over-the-counter pain reliever, such as acetaminophen (Tylenol) or ibuprofen (Advil, Motrin). For dry eye, lubricating eye drops or gels can help. An eye patch can also be helpful to protect the eye, especially at night.

What are the potential complications of Bell’s palsy?

The outlook with Bell’s palsy is usually very good. About 85% of people recover fully in about three weeks. And most people regain full facial control within six months. A small number of people have persistent or permanent facial paralysis or weakness. This can range from mild to severe impairment. For people with lingering facial nerve problems, plastic surgery may help. Facial reanimation surgery corrects and restores facial movements with techniques including eyelid lifts, facial implants, and nerve grafts.

Partial or complete blindness is a possible complication of Bell’s palsy. It can happen when eyes are excessively dry for a prolonged time or there is extensive scratching of the cornea. Using eye lubricants and a patch can help prevent this.

Finally, if nerve fibers regrow abnormally (aberrant regeneration), there is a risk of synkinesis. In synkinesis, the nerve fibers grow to innervate different muscles than they originally supplied. It results in involuntary muscle movements in one area that occur when you voluntarily move muscles in another area. For example, your eye might close when you smile. Physical therapy, botulinum toxin (Botox) injections, and surgery may correct the problem.

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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2020 Jun 17
  1. Bell’s Palsy. American Academy of Ophthalmology.
  2. Bell’s Palsy. Mayo Foundation for Medical Education and Research.
  3. Bell’s Palsy. National Organization for Rare Disorders.
  4. Bell’s Palsy Fact Sheet. National Institute of Neurological Disorders and Stroke.
  5. Synkinesis. Facial Paralysis and Bell’s Palsy Foundation.
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