Bell's Palsy

Bell's palsy is a sudden weakness or loss of function of certain facial muscles, usually on one side of the face, caused by swelling of a facial nerve.

Half a Face

Fifteen-year-old Shelly woke up one morning feeling as though she had just received a shot of novocaine from the dentist. When she looked in the mirror, she saw that her face seemed limp on one side. She could not smile, and only one side of her face seemed to work. Shelly screamed for her parents and they came running. When they saw her face, they became worried that she had had a stroke * or had developed a brain tumor. They rushed her to the hospital emergency room.

The Scottish scientist Sir Charles Bell (1774–1842) studied anatomy (the structure of organisms). His investigations of the brain have been called the “Magna Carta of Neurology.” The Magna Carta, or “great charter,” is a famous document in English history that spelled out governmental law and people's rights, so this comparison is quite a compliment to Bell, who received the first medal awarded by the Royal Society of Great Britain for his book, Idea of a New Anatomy of the Brain (1811).

Bell was the first to describe how sensory neurons (nerve cells) carry messages to the brain and how motor neurons carry messages to muscles and glands. Because of his work with nerve anatomy, Bell's palsy was named after him.

It took three weeks for Shelly's condition to go away, and those three weeks felt more like three years to Shelly, but she was grateful that the condition was not something more serious.

What Is Bell's Palsy?

Bell's palsy is a condition that occurs when the facial nerve becomes irritated. The facial nerve runs from the brain through a small hole in the skull. Sometimes the facial nerve becomes irritated or swollen. The irritated nerve does not send normal signals to the muscles on one side of the face. The result is partial or complete loss of muscle function (called palsy).

The symptoms of Bell's palsy begin suddenly and usually worsen over two to five days. The sudden numbness or weakness characteristic of Bell's palsy gets worse during the day and the face feels stiff and pulls to one side. People with Bell's palsy typically have problems closing one eye and cannot wrinkle their forehead. They may feel pain behind the ear, they may experience involuntary facial movements called “tics,” and hearing in the ear on the affected side may be very sensitive. They also may drool and have trouble eating and talking.

People with a stroke can look as if they have Bell's palsy, so it is important to visit a doctor to find out what is causing facial paralysis. People with Bell's palsy often fear a brain tumor, but the symptoms of a brain tumor usually occur more gradually than the sudden start of Bell's palsy.

Bell's palsy causes muscle weakness or loss of muscle function on one side of the face, which can result in a lopsided appearance.

Bell's palsy causes muscle weakness or loss of muscle function on one side of the face, which can result in a lopsided appearance.
Dr. P. Marazzi/Science Source.

Ramsay Hunt syndrome is caused by the varicella-zoster virus (VΖV). This virus, a strain of the herpes virus, also causes chickenpox. This virus may remain dormant in the body for decades, which explains why individuals over the age of 50 are most often afflicted.

What Causes Bell's Palsy?

Bell's palsy is considered an idiopathic (id-e-o-PATH-ik) disease, which means that its cause is unknown or uncertain. Most scientists believe that Bell's palsy is caused by irritation of the facial nerve after a viral infection such as herpes zoster (which causes shingles) or herpes simplex (the cold sore virus). It also may be related to a blow to the face that damages the nerve or to conditions such as Lyme disease, diabetes, and high blood pressure.

Bell's palsy can happen to men and women of all ages but is most common between the ages of 30 and 60. Pregnant women and people who have diabetes, a cold, or the flu are more susceptible than others. One person in 60 to 70 develops Bell's palsy during his or her lifetime, which translates to about 40,000 people per year in the United States.

How Is Bell's Palsy Treated?

Eighty percent of people with Bell's palsy begin to recover several weeks after the onset of symptoms, and they recover completely within several months without treatment. A few people never recover completely, and some of their symptoms continue permanently.

During recovery, the biggest concern is protecting the exposed eye from dryness and injury. Doctors sometimes prescribe antiviral medications during the first five to six days of the onset of Bell's palsy, and anti-inflammatory drugs sometimes help reduce swelling of the nerve.

See also Chickenpox (Varicella) • Diabetes • Herpes Simplex Virus Infections • Hypertension • Lyme Disease • Paralysis • Shingles (Herpes Zoster)


Books and Articles

Gagyor, I., et al. “Antiviral Treatment for Bell's Palsy.” Cochrane, May 4, 2015. (accessed November 20, 2015).


Facial Paralysis and Bell's Palsy Foundation. “Bell's Palsy.” (accessed June 21, 2016).


American Academy of Otolaryngology—Head and Neck Surgery. 1650 Diagonal Rd., Alexandria, NA 22314-2857. Telephone: 703-836-4444. Website: (accessed November 20, 2015).

National Institute of Neurological Disorders and Stroke. PO Box 5801, Bethesda, MD 20824. Telephone: 301-496-5751. Toll-free: 800-352-9424. Website: (accessed October 7, 2015.

* stroke is a brain-damaging event usually caused by interference with blood flow to the brain. A stroke may occur when a blood vessel supplying the brain becomes clogged or bursts, depriving brain tissue of oxygen. As a result, nerve cells in the affected area of the brain, and the specific body parts they control, do not properly function.

Disclaimer:   This information is not a tool for self-diagnosis or a substitute for professional care.

(MLA 8th Edition)