Bell's Palsy

Bell's Paralysis, Unilateral Facial Paralysis, Facial Palsy

What is Bell's palsy?

Bell’s palsy is a temporary paralysis or weakness that usually occurs on one side of the face when there is damage to facial nerves. The condition may also be referred to as acute idiopathic facial palsy or Bell’s palsy syndrome.

Bell’s palsy is the most common cause of facial paralysis. The paralytic symptoms may begin suddenly and peak within 48 hours. Most patients improve gradually and their symptoms diminish or disappear within two weeks. Some may experience the effects for six months to a year. A few people may experience permanent facial muscle shrinkage and a distorted appearance, such as an asymmetric smile that curves up on one side and down on the other.

The affected areas may start at the forehead and stretch down to the chin and over to the ear, usually on one side of the face. This can cause the mouth and affected eyelid to droop and sag. The ability to blink may be hindered to the point that the eye dries out from lack of lubrication. Dryness makes the eyes more susceptible to injury or infection. Debris can more easily fly into the eyes, making them more vulnerable to injury. Drooling and slurred speech can also occur. Some people may experience hearing loss or hypersensitivity to sound on one side.

The causes of Bell’s palsy are not well understood. Viral infections, such as the herpes viruses that cause cold sores and shingles may be involved. The viruses may cause inflammation and pressure along the facial nerve, contributing to the paralysis. For some people, the facial palsy may be preceded by influenza or respiratory illness. Other causes may include facial trauma, such as from an automobile accident or sports injury.

Treatment for Bell’s palsy depends on the cause of the facial nerve damage. Antiviral medications and corticosteroids may be prescribed to fight infection and inflammation and pain relievers may be taken for jaw, ear or mouth pain that may accompany the paralysis. However, even after a patient fully recovers, there can be a relapse. One in five patients has recurrences of facial palsy.

Bell’s palsy affects nearly 40,000 people a year in the United States, according to the National Institute of Neurological Disorders and Stroke (NINDS). People who have diabetes, upper respiratory illnesses and pregnant women are most often affected. The condition can occur at any age and affects men and women about equally. Children under age 15 and adults over age 60 are less likely to develop it.

Bell's Palsy signs and symptoms

  • Sudden paralysis on one side of the face, including muscles to the eyelid.
  • Pain behind the ear on the affected side.
  • Flat, expressionless features on one side of the face.
  • Distorted smiles and frowns.
  • Drooling.
  • Changes in taste, salivation or tear formation (sometimes).


Unknown. The paralysis is probably caused by swelling of the facial nerve. The swelling may be caused by a virus; an autoimmune disease; or a decrease in blood flow and pressure on the facial nerve as it passes through the temporal bone of the skull.

Risk increases with

Exposure to cold.

Preventive measures

Cannot be prevented at present.

Expected outcomes

  • Bell's palsy is distressing, but it is not dangerous. The extent of nerve damage determines the extent of recovery.
  • Improvement is gradual and recovery time varies, sometimes requiring many months.
  • Patients with mild facial paralysis usually recover completely within several months. Patients with severe facial paralysis recover completely in 80% to 90% of cases.
  • Surgery can sometimes improve facial appearance and muscle function in patients who do not recover fully.

Possible complications

  • Eye irritation or injury because the eye does not close properly and is exposed to dust. If unprotected, the eye may develop ulcers on the cornea.
  • Tooth decay and gum disease due to reduced saliva and impairment of chewing.
  • Psychological and self-esteem problems.

Bell's palsy treatment

  • Computed tomography (CT) or magnetic resonance imaging (MRI), and laboratory studies may occasionally be recommended to rule out other causes of pressure on the facial nerve.
  • Electrical tests of the facial nerves (electromyography) may be used to determine the extent of nerve damage.
  • If you have pain, apply heat to the painful area twice a day. Wring out a small towel soaked in hot water and apply for 15 minutes. Cover or close the eye during heat treatments.
  • If you cannot wink or close your eye well, buy a pair of wrap-around, plastic bubble goggles. Wear them to protect your eye from dirt, dust and dryness. You may buy goggles from a sporting goods store or optician.
  • At night, apply an eye patch to shut the lid so the eye stays moist and protected. Occasionally, a patch will be necessary during the daytime.
  • As muscle strength returns, use facial massage and exercises. Massage muscles of the forehead, cheek, lips and eyes using cream or oil. Exercise the weak muscles in front of a mirror. Open and close the eye, wink, smile and bare your teeth. Perform the massage and exercise for 15 or 20 minutes several times a day.
  • Brush and floss teeth more often to keep the mouth healthy.
  • Surgery on the facial nerve (rare).

Additional Information


  • Methylcellulose eye drops for comfort and protection of the exposed eye.
  • Short courses of cortisone drugs are usually beneficial to reduce swelling and inflammation of the affected nerve.


Maintain your normal activities. Rest does not help Bell's palsy.


A soft diet is often necessary.

Notify your physician if

  • You or a family member has symptoms of Bell's palsy.
  • Your eye becomes red or irritated, despite treatment.
  • You cannot prevent saliva from drooling from your mouth.
  • Pain worsens.
  • Fever occurs.