Bell’s Palsy

Overview

Bell’s palsy occurs when one of the nerves that controls muscles in the face becomes injured or stops working properly. This nerve connects the brain to muscles that control facial expression and also carries information about taste.

Symptoms of Bell’s palsy appear suddenly over 2 to 3 days and generally begin to improve after a few weeks. People with Bell’s palsy usually recover some or all facial function within a few weeks to six months. Sometimes, facial weakness lasts longer or is permanent. In rare cases, recovery of the facial nerve results in an abnormal connection between jaw muscles and the gland near the eye that produces tears. Eyes watering while chewing is also known as “crocodile tears.”

In rare cases, Bell’s palsy can affect both sides of the face.

Related Terms: Bell’s palsy is also known as facial nerve palsy.

Signs and Symptoms

Symptoms of Bell’s palsy include:

• Sudden weakness or paralysis on one side of the face
• A drooping eyebrow and mouth
• Drooling from one side of the mouth
• Difficulty closing one eyelid, which causes dry eye

Most often, these symptoms lead to noticeable changes in the shape of the face.

People living with Bell’s palsy also may develop:

• Pain or unusual sensations in the face
• A lot of tears in one eye
• Problems with taste
• Sensitivity to loud noises
• Pain around the jaw and behind the ear
• Problems eating or drinking

Symptoms vary from person to person and can be mild to severe.

Related Health Effects

People with Bell’s palsy can have nerve problems in the head that may cause weakness or paralysis on one side of the face. Diabetes is a known risk factor for focal neuropathies, including Bell’s palsy.

Herpes zoster oticus, also known as Ramsay Hunt Syndrome, is a related condition caused by a virus that can cause paralysis of facial nerves.

Causes and Risk Factors

Bell’s palsy can affect anyone of any sex or age, but most often affects people ages 15-45.

The exact cause of Bell’s palsy is unknown. Some evidence suggests the facial nerve becomes irritated and swollen, but it’s not clear why this happens.

Risk factors for Bell’s palsy include:

• Pregnancy
• Preeclampsia (high blood pressure during pregnancy)
• Obesity
• Hypertension
• Diabetes
• Colds or other infections in the nose, throat, or lungs

Possible triggers of Bell’s palsy may include:

• A virus that has been inactive in the body becomes active again (such as the herpes or chickenpox virus)
• A weakened immune system due to stress, lack of sleep deprivation, injury, minor illness, or certain autoimmune conditions
• Infection of the facial nerve that causes irritation and swelling, such as Lyme disease

Diagnosis

A healthcare provider will perform a physical exam to check for upper and lower facial muscle weakness on one side of the face, including the forehead, eyelid, and mouth. The healthcare provider will ask when symptoms began and will check for other possible causes of facial paralysis.

Bell’s palsy is diagnosed when no other cause of facial paralysis can be found.

Routine laboratory or imaging tests (scans) are usually not necessary. However, these tests can sometimes help confirm a diagnosis or point to other conditions that cause facial weakness. Imaging tests may be useful if facial weakness gets worse or if taste and hearing are affected.

Other tests include:

• Tests that check how well the facial nerve and muscles are working, and how likely recovery is
• Blood tests to check for infections like Lyme disease and other viruses that can cause similar symptoms

Treatment and Management

There is no cure for Bell’s palsy, but most people recover on their own within weeks to months. Common treatments for symptoms include medicines, use of artificial tears, or other ways to protect the eye (if the eye cannot be completely closed). If recovery is incomplete or problems develop, injections, surgery, or other therapies may be used.

Medicines

A healthcare provider may prescribe steroid pills for newly diagnosed Bell’s palsy. In most cases, these medicines should be started within three days of symptoms starting to reduce irritation and swelling to improve the chance of recovery. Some people with Bell’s palsy may not respond well to or be able to take these medicines.

Antiviral medicines may also be prescribed to improve the chance of recovery of facial movement.

People with Bell’s palsy who have pain may find relief by taking non-prescription pain medicines such as aspirin, acetaminophen, or ibuprofen. To avoid dangerous drug interactions, people should first check with their healthcare provider or pharmacist before taking over-the-counter drugs if they already take prescription medicines.

Eye Protection

If a person with Bell’s palsy has trouble closing one or both eyelids, artificial tears or eye patches can help keep the eye moist and protect it from dirt or injury, especially while sleeping.

Other Therapies

Physical therapy, facial massage, or acupuncture may help facial movement and reduce pain.

Surgery

In some cases, reconstructive surgery could fix a permanently crooked smile or an eyelid that will not close.

Find Clinical Trials

Clinical trials uncover better ways to prevent, diagnose, treat, and understand diseases and conditions. To ensure results apply to everyone, volunteers of all ages, sexes, and backgrounds, including both healthy individuals and those with specific medical conditions, are needed. Find clinical trials on Bell’s Palsy.

Community Support

The following organizations provide information and support for people with Bell’s palsy and related rare diseases:

• Genetic and Rare Diseases Information Center
• National Organization for Rare Disorders

Note: This resource list is for informational purposes only. It is not comprehensive, and an organization’s inclusion does not constitute an endorsement by NIH.  

Research Information

The National Institutes of Health (NIH) is the largest public funder of biomedical research in the world. NIH invests most of its budget in medical research seeking to enhance life and to reduce illness and disability. NIH-funded research has led to breakthroughs and new treatments helping people live longer, healthier lives, and building the research foundation that drives discovery.  

NIH funds research on neurological disorders. Some of this research focuses on learning more about the nerve mechanisms involved in facial movement and control and the circumstances that lead to nerve damage and facial paralysis.

This research may help scientists find out what causes Bell’s palsy. This information can lead to the discovery of new treatments.

Current research areas include:

• Studying how facial paralysis surgery affects people’s function and quality of life
• Looking at a possible treatment for eye problems that can occur in people with facial nerve palsy
• Studying whether electrical stimulation can treat facial paralysis or weakness

Find NIH-funded research projects using NIH RePORTER, a searchable database of current and past research projects supported by NIH and other federal agencies.