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Bell's Palsy

Partial or complete paralysis of the facial muscles of one side of a person's face. It is caused by damage to the seventh cranial nerve. It is usually temporary but it may recur.

PubMed Health Glossary
(Source: NIH - National Cancer Institute)

About Bell's Palsy

Bell's palsy is a form of temporary facial paralysis resulting from damage or trauma to the 7th cranial nerve, one of the facial nerves. It is the most common cause of facial paralysis. Generally, Bell's palsy affects only one side of the face, however, in rare cases, it can affect both sides.

Symptoms usually begin suddenly and reach their peak within 72 hours, and can range in severity from mild weakness to total paralysis. Symptoms vary among individuals and include sudden weakness on one side of the face, drooping eyelid or corner of the mouth, drooling, dry eye or mouth, altered taste, and excessive tearing in the eye. Bell's palsy can cause significant facial distortion.

The exact cause of Bell's palsy isn't known, but many scientists believe that reactivation of a dormant viral infection can cause the facial nerve to swell and becomes inflamed. Several other conditions can cause facial paralysis that might be diagnosed as Bell's palsy....Read more about Bell's Palsy
NIH - National Institute of Neurological Disorders and Stroke

What works? Research summarized

Evidence reviews

Acupuncture for Bell's palsy

Bell's palsy or idiopathic facial palsy is the most common disorder affecting the facial nerves and results in weakness or paralysis on one side of the face. The paralysis causes distortion of the face and interferes with normal functions, such as closing the eye and eating. It is thought to be caused by inflammation of the facial nerve.

Surgical operation for Bell's palsy (idiopathic facial paralysis)

Bell’s palsy is a paralysis of the muscles of the face, usually on one side, that has no known underlying cause. The symptoms probably occur when a nerve in the face is trapped and swollen. People with Bell's palsy generally recover but there is a small group who do not. Some surgeons have thought that an operation to free the nerve could improve recovery. We did this review to assess the effects of surgery for Bell's palsy compared with no treatment, other types of surgery, sham (fake) treatment or treatment with medicines.

High pressure (hyperbaric) oxygen therapy for Bell's palsy

Bell's palsy is a weakness of one side of the face that is diagnosed after other causes of facial weakness have been ruled out. It is a 'diagnosis of exclusion'. Bell's palsy may be caused by a virus affecting the facial nerve. Standard treatment includes steroids to help settle swelling of the facial nerve, whereas antiviral treatment does not appear to help. In hyperbaric oxygen therapy, the person undergoing treatment breathes 100% oxygen in a pressurised chamber for about one hour (called a 'dive'). This may produce more dissolved oxygen in the facial nerve and might reduce nerve damage in Bell's palsy. We searched for evidence from randomised controlled trials on hyperbaric oxygen therapy in adults with moderate to severe Bell's palsy. Our searches revealed no trials that met the inclusion criteria for the review. We found very low quality evidence from one trial to suggest that hyperbaric oxygen therapy might be beneficial for moderate to severe Bell's palsy. The trial involved 79 participants and compared hyperbaric oxygen therapy to prednisone, a corticosteroid, which is a proven active treatment. The participants did not know which treatment they were being given. Those treated with hyperbaric oxygen recovered more quickly and recovered normal facial movement more often (95% versus 76%). All participants tolerated the treatment well, and there were no major complications. The quality of evidence from this trial was very low because the assessors of facial function were aware of which treatment each participant had been given, which introduces a high risk of bias. There is therefore no high quality evidence on which to base conclusions about the efficacy of hyperbaric oxygen therapy in Bell's palsy.

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Summaries for consumers

Acupuncture for Bell's palsy

Bell's palsy or idiopathic facial palsy is the most common disorder affecting the facial nerves and results in weakness or paralysis on one side of the face. The paralysis causes distortion of the face and interferes with normal functions, such as closing the eye and eating. It is thought to be caused by inflammation of the facial nerve.

Surgical operation for Bell's palsy (idiopathic facial paralysis)

Bell’s palsy is a paralysis of the muscles of the face, usually on one side, that has no known underlying cause. The symptoms probably occur when a nerve in the face is trapped and swollen. People with Bell's palsy generally recover but there is a small group who do not. Some surgeons have thought that an operation to free the nerve could improve recovery. We did this review to assess the effects of surgery for Bell's palsy compared with no treatment, other types of surgery, sham (fake) treatment or treatment with medicines.

High pressure (hyperbaric) oxygen therapy for Bell's palsy

Bell's palsy is a weakness of one side of the face that is diagnosed after other causes of facial weakness have been ruled out. It is a 'diagnosis of exclusion'. Bell's palsy may be caused by a virus affecting the facial nerve. Standard treatment includes steroids to help settle swelling of the facial nerve, whereas antiviral treatment does not appear to help. In hyperbaric oxygen therapy, the person undergoing treatment breathes 100% oxygen in a pressurised chamber for about one hour (called a 'dive'). This may produce more dissolved oxygen in the facial nerve and might reduce nerve damage in Bell's palsy. We searched for evidence from randomised controlled trials on hyperbaric oxygen therapy in adults with moderate to severe Bell's palsy. Our searches revealed no trials that met the inclusion criteria for the review. We found very low quality evidence from one trial to suggest that hyperbaric oxygen therapy might be beneficial for moderate to severe Bell's palsy. The trial involved 79 participants and compared hyperbaric oxygen therapy to prednisone, a corticosteroid, which is a proven active treatment. The participants did not know which treatment they were being given. Those treated with hyperbaric oxygen recovered more quickly and recovered normal facial movement more often (95% versus 76%). All participants tolerated the treatment well, and there were no major complications. The quality of evidence from this trial was very low because the assessors of facial function were aware of which treatment each participant had been given, which introduces a high risk of bias. There is therefore no high quality evidence on which to base conclusions about the efficacy of hyperbaric oxygen therapy in Bell's palsy.

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Terms to know

Cranial Nerves
Cranial nerves are nerves emerging directly from the brain, in contrast to spinal nerves (which emerge from various segments of the spinal cord). Cranial nerves exchange information between the brain and parts of the body, primarily to and from regions of the head and neck.
Muscles
Muscles function to produce force and motion. They are primarily responsible for maintaining and changing posture, locomotion, as well as movement of internal organs, such as the contraction of the heart and the movement of food through the digestive system.
Nerves
A bundle of fibers that receives and sends messages between the body and the brain. The messages are sent by chemical and electrical changes in the cells that make up the nerves.
Oral Herpes (Cold Sore)
A type of herpes simplex. An outbreak typically causes small blisters or sores on or around the mouth. The sores typically heal within 2-3 weeks, but the herpes virus remains, periodically reactivating (in symptomatic people) to create sores in the same area of the mouth or face.
Viral Meningitis
Inflammation of the membranes surrounding the brain and spinal cord due to a viral infection.

More about Bell's Palsy

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Also called: Facial nerve palsy, Facial nerve paralysis, Facial palsy, Bell palsy, Bells palsy

Other terms to know: See all 5
Cranial Nerves, Muscles, Nerves

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