Bell’s palsy is a condition that causes sudden weakness or paralysis on one side of the face. It happens when the facial nerve, which controls many of the muscles used for facial expression, is affected. In most cases, the condition develops over hours to a few days and eventually improves.
Although Bell’s palsy is usually temporary, sudden facial weakness should always be taken seriously because a stroke can also cause facial drooping. Knowing the difference between the two is important, particularly when symptoms appear suddenly.
What Is Bell’s Palsy?
Bell’s palsy is a form of temporary facial paralysis caused by dysfunction of the seventh cranial nerve, also called the facial nerve. This nerve controls the muscles responsible for facial expressions and also has roles in taste, tear production, and some functions involving the ear.
The condition usually affects only one side of the face. A person may notice that one side of their mouth droops, their smile looks uneven, or they cannot fully close one eye.
Bell’s palsy is different from facial weakness caused by a brain injury, stroke, tumor, or other neurological condition. The exact cause of typical Bell’s palsy is not known, although inflammation and swelling around the facial nerve are thought to play an important role. (AAFP)
What Causes Bell’s Palsy?
The exact cause remains uncertain. Researchers believe that inflammation or swelling of the facial nerve may interfere with its normal function.
Viral infections have been proposed as possible triggers because some viruses can remain inactive in the body and later become reactivated. However, Bell’s palsy is generally described as idiopathic, meaning that no definite cause can be identified in an individual case. (AAFP)
Some conditions and circumstances have been associated with a higher risk of developing facial nerve palsy, including:
- Pregnancy
- Diabetes
- Certain infections
- Previous episodes of facial nerve palsy
- A family history of the condition
It is important not to assume that stress, a particular food, or another everyday activity directly caused an episode unless a healthcare professional identifies a specific underlying cause.
Symptoms
Symptoms usually appear relatively quickly and affect one side of the face. Common signs include:
- Weakness or paralysis on one side of the face
- A drooping corner of the mouth
- An uneven smile
- Difficulty closing one eye
- Drooling
- Difficulty drinking or eating
- Changes in taste
- A dry or unusually watery eye
- Increased sensitivity to loud sounds
- Pain around or behind the ear
- Difficulty making normal facial expressions
Some people notice facial weakness before they realize what is happening. For example, they may have trouble smiling, raising an eyebrow, or closing one eye.
Symptoms can vary considerably from person to person depending on how severely the facial nerve is affected. (Barnsley Hospital)
What Muscles Are Affected?
Because the facial nerve controls the muscles used for facial expression, Bell’s palsy can affect movements involving the:
- Forehead
- Eyelids
- Cheeks
- Nose
- Lips
- Mouth
This is why a person may have difficulty raising an eyebrow, closing an eye, smiling, frowning, or moving one side of the mouth normally.
The facial nerve also has functions beyond movement, so some people experience changes in taste, tear production, or sensitivity to sound.
Bell’s Palsy vs. Stroke: What Is the Difference?
One of the most important questions when someone develops facial weakness is whether it could be a stroke.
Bell’s palsy typically causes weakness involving the forehead, eye, and mouth on one side of the face. A stroke can also cause facial drooping, but it often occurs alongside other neurological symptoms.
Warning signs that may indicate a stroke include:
- Sudden weakness or numbness in an arm or leg
- Difficulty speaking or understanding speech
- Confusion
- Severe dizziness or problems with balance
- Sudden vision problems
- A severe, sudden headache
- Facial drooping accompanied by weakness elsewhere in the body
If facial drooping occurs together with arm weakness or speech problems, seek emergency medical care immediately. Stroke is a medical emergency and should not be assumed to be Bell’s palsy. (nhs.uk)
Even when facial weakness appears to fit the pattern of Bell’s palsy, prompt medical assessment is recommended because treatment is most useful when started early.
How to Diagnose?
Bell’s palsy is usually diagnosed from the person's symptoms and a physical examination.
A healthcare professional may ask when the weakness started and examine movements such as:
- Raising the eyebrows
- Closing the eyes
- Smiling
- Showing the teeth
- Frowning
- Puckering the lips
The clinician will also look for symptoms that could suggest another cause of facial weakness.
Routine scans and laboratory tests are generally not necessary when the symptoms strongly fit typical Bell’s palsy. Additional testing may be considered when symptoms are unusual, recurrent, or suggest another condition. (AAFP)
Treatment
Treatment depends on the severity of the weakness and how soon medical care is received.
Corticosteroids
Corticosteroids are the main medical treatment for Bell’s palsy. They reduce inflammation and can improve the likelihood of complete recovery.
They work best when started early, generally within the first 72 hours after symptoms begin. A healthcare professional should determine whether steroids are appropriate because they are not suitable for everyone and can have side effects. (AAFP)
Antiviral Medication
Antiviral medicines may sometimes be prescribed alongside corticosteroids, particularly when a viral cause is suspected or in certain cases.
However, antiviral medication alone is not considered an effective treatment for typical Bell’s palsy. Evidence reviewed by the American Academy of Family Physicians supports corticosteroids as the primary treatment, while the additional benefit of routinely adding an antiviral remains less certain. (AAFP)
Protecting the Eye
Eye care is one of the most important parts of managing Bell’s palsy.
If the affected eyelid cannot close completely, the surface of the eye can become dry and irritated. In more serious cases, this can damage the cornea.
Treatment may include:
- Artificial tears during the day
- Lubricating eye ointment
- Protecting or gently taping the eyelid closed during sleep
- Medical evaluation if the eye becomes painful, red, or irritated
Anyone who cannot properly close an affected eye should discuss eye protection with a healthcare professional. (AAFP)
Physical Therapy and Facial Exercises
Some people with severe or persistent facial weakness may benefit from facial physical therapy. Exercises should not be performed aggressively. Forceful or excessive facial movements during recovery may potentially contribute to abnormal muscle coordination, known as synkinesis. A therapist familiar with facial nerve disorders can recommend appropriate exercises based on the stage of recovery. (AAFP)
Physical therapy may be particularly useful when significant weakness persists or normal facial movement does not return as expected.
What About Acupuncture?
Acupuncture is sometimes promoted as a treatment for facial paralysis. However, current evidence is not strong enough to establish it as a standard treatment for Bell’s palsy. People considering complementary treatments should discuss them with a healthcare professional rather than using them instead of evidence-based treatment. (AAFP)
How Long Does Bell’s Palsy Last?
Recovery varies from person to person.
Many people begin noticing improvement within a few weeks. A large proportion eventually recover completely, although the amount of time needed can range from several weeks to several months. Some people take longer to recover, particularly when the initial nerve weakness is severe. (AAFP)
In general:
- Early improvement may occur within 2 to 3 weeks.
- Many people recover substantially within several months.
- More severe cases can take longer.
- A smaller number of people are left with persistent facial weakness or other symptoms.
The severity of the initial facial paralysis is an important factor in predicting recovery.
Is Bell’s Palsy Permanent?
Bell’s palsy is usually temporary, and most people experience substantial or complete recovery.
However, permanent or long-lasting symptoms can occur in some cases. Possible ongoing problems include facial weakness, involuntary facial movements, difficulty closing the eye, changes in taste, facial discomfort, or excessive tearing.
If facial function is not improving as expected, or significant weakness remains for several months, further evaluation by a specialist may be appropriate. (AAFP)
What Happens If Bell’s Palsy Is Not Treated?
Some people recover without medical treatment, but that does not mean medical evaluation is unnecessary.
The most important reason to seek care quickly is that corticosteroid treatment is most beneficial when started early. In addition, an inability to close the eye can put the eye at risk of dryness and injury. (AAFP)
Untreated or inadequately managed cases may also have a greater risk of prolonged symptoms, depending on the severity of the nerve involvement.
Can Bell’s Palsy Come Back?
Most people experience Bell’s palsy only once, but recurrence is possible.
A repeat episode may require additional evaluation to make sure there is not another underlying cause of recurrent facial weakness. A family history may also be relevant when discussing recurrent episodes with a healthcare professional. (Chelsea & Westminster Hospital)
Is Bell’s Palsy Contagious?
Bell’s palsy itself is not considered contagious. You cannot catch Bell’s palsy from another person through ordinary contact.
Although viral infections are thought to be possible triggers in some cases, this does not mean that the facial paralysis itself can be passed from one person to another.
Bell’s Palsy During Pregnancy
Bell’s palsy can occur during pregnancy. If facial weakness develops during pregnancy, it is important to have it medically assessed rather than assuming it is simply related to pregnancy.
Treatment decisions, particularly the use of corticosteroids, should be made with a healthcare professional who can consider the individual's stage of pregnancy and overall health. (AAFP)
When Should You See a Doctor?
Sudden facial weakness deserves prompt medical assessment, particularly when it is the first episode.
Seek urgent medical attention if facial weakness occurs with:
- Arm or leg weakness
- Trouble speaking
- Confusion
- Severe dizziness
- Loss of balance
- Sudden vision changes
- A severe headache
- Other sudden neurological symptoms
These symptoms can indicate a stroke rather than Bell’s palsy. (nhs.uk)
You should also seek medical advice if the affected eye cannot close, because the eye may need protection from dryness and injury.
Frequently Asked Questions
Does Bell’s palsy go away?
In most cases, yes. Many people begin improving within a few weeks and eventually recover substantially or completely. Recovery can take several months, especially in more severe cases.
Is Bell’s palsy caused by stress?
Stress is sometimes suggested as a possible trigger, but there is no single proven cause for typical Bell’s palsy. The condition is generally considered idiopathic, with inflammation of the facial nerve and possible viral triggers among the proposed explanations.
Can you exercise with Bell’s palsy?
Gentle facial rehabilitation may be useful for some people, particularly when movement begins to return or weakness persists. However, forceful facial exercises should be avoided unless recommended by a qualified healthcare professional.
Can Bell’s palsy affect both sides of the face?
It usually affects one side. In rare cases, facial weakness can occur on both sides, which may require additional investigation to determine the cause. (Chelsea & Westminster Hospital)
Can Bell’s palsy cause ear pain?
Yes. Pain around or behind the affected ear can occur before or during facial weakness. (Barnsley Hospital)
Is Bell’s palsy a form of stroke?
No. Bell’s palsy involves dysfunction of the facial nerve, while a stroke occurs when blood flow to part of the brain is interrupted or bleeding occurs in the brain. However, stroke can also cause facial weakness, which is why sudden facial drooping should be assessed promptly.
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