Bell's Palsy: Symptoms, Causes, and Treatment
Updated: 2 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 2026
Quick Answer
Bell's palsy is a condition that causes sudden weakness in the muscles on one side of the face, making it droop and the eye hard to close. The facial nerve becomes inflamed, usually related to a viral infection. Most people recover fully, and corticosteroids work best started within several days; protecting the affected eye is essential.
What the research says
Corticosteroids lower the risk of incomplete recovery. A Cochrane review of 7 trials (895 participants) found that 79 of 452 people (17%) given corticosteroids had incomplete recovery of facial movement at six months or more, compared with 125 of 447 (28%) in the control group (risk ratio 0.63; 95% CI 0.50 to 0.80). About 10 people (95% CI 6 to 20) need to be treated to avoid one incomplete recovery, and motor synkinesis was also less common (RR 0.64; 95% CI 0.45 to 0.91), with no significant difference in adverse effects versus placebo (Madhok et al., Cochrane Database Syst Rev, 2016) [3].
Adding an antiviral to a steroid has little or no effect on recovery, and antivirals alone do not help. In a Cochrane review of 14 trials (2,488 participants), antivirals plus corticosteroids versus corticosteroids alone showed little or no difference in incomplete recovery (RR 0.81; 95% CI 0.38 to 1.74; 3 trials, 766 participants; low-certainty evidence), and antivirals alone had no clear effect versus placebo (RR 1.10; 95% CI 0.87 to 1.40). The combination probably did reduce late sequelae such as synkinesis or crocodile tears (RR 0.56; 95% CI 0.36 to 0.87; moderate-certainty evidence) (Gagyor et al., Cochrane Database Syst Rev, 2019) [4].
Guideline advice: steroids early, no antiviral alone, protect the eye. The American Academy of Otolaryngology–Head and Neck Surgery guideline strongly recommends oral steroids within 72 hours of symptom onset for people 16 and older, advises against oral antivirals alone, and calls for eye protection when the eye does not close fully. It also advises against routine blood tests and routine imaging for new-onset Bell's palsy (Baugh et al., Otolaryngol Head Neck Surg, 2013) [5].
What is Bell's palsy?
Bell's palsy is a condition that causes sudden weakness in the muscles on one side of the face. The weakness makes half of the face appear to droop, smiles become one-sided, and the eye on the affected side becomes hard to close. The good news is that the weakness is usually short-term: symptoms typically start to improve within a few weeks, with complete recovery in about six months.
This guide explains what Bell's palsy is, the symptoms that come on suddenly, what researchers believe causes it, who is most at risk, how it is diagnosed when it mimics a stroke, and the treatments and home care steps that support recovery, especially protecting the eye that will not close.
Bell's palsy is a condition that causes sudden weakness in the muscles on one side of the face. Often the weakness is short-term and improves over weeks. The weakness makes half of the face appear to droop. Smiles are one-sided, and the eye on the affected side is hard to close.
Bell's palsy also is known as acute peripheral facial palsy of unknown cause. It can occur at any age. The exact cause is not known. Experts think it is caused by swelling and irritation of the nerve that controls the muscles on one side of the face. Bell's palsy could be caused by a reaction that occurs after a viral infection.
Symptoms usually start to improve within a few weeks, with complete recovery in about six months. A small number of people continue to have some Bell's palsy symptoms for life. Rarely, Bell's palsy occurs more than once.
What are the symptoms of Bell's palsy?
Symptoms of Bell's palsy come on suddenly, within hours to days. They can range from mild weakness to total paralysis on one side of the face.
The nerve that controls facial muscles passes through a narrow corridor of bone on its way to the face. Facial weakness or paralysis may cause one corner of the mouth to droop, and the mouth may not be able to retain saliva on the paralyzed side of the face. The condition also may make it difficult to close the eye on the affected side of the face.
Other symptoms may include facial droop and trouble making facial expressions, such as closing an eye or smiling, drooling, pain around the jaw or pain in or behind the ear on the affected side, increased sensitivity to sound on the affected side, headache, loss of taste, and changes in the amount of tears and saliva produced. Rarely, Bell's palsy can affect the nerves on both sides of the face.
Symptom | What it looks like |
Facial weakness or paralysis | Mild weakness to total paralysis on one side of the face, within hours to days |
Facial droop | One corner of the mouth droops; half of the face appears to droop |
Trouble with expressions | Difficulty closing an eye or smiling |
Drooling | The mouth may not retain saliva on the paralyzed side |
Pain | Around the jaw or in or behind the ear on the affected side |
Sound sensitivity | Increased sensitivity to sound on the affected side |
Headache | Headache on the affected side |
Taste changes | Loss of taste |
Fluid changes | Changes in the amount of tears and saliva produced |
Why is sudden facial weakness an emergency?
Seek medical help right away if you experience any type of paralysis because you may be having a stroke. Bell's palsy is not caused by a stroke, but the symptoms of both conditions are similar.
If you have facial weakness or drooping, see your health care professional to find out the cause and the severity of the illness.
What causes Bell's palsy?
Although the exact reason Bell's palsy occurs is not clear, it is often related to having a viral infection. The nerve that controls facial muscles passes through a narrow corridor of bone on its way to the face. In Bell's palsy, that nerve becomes inflamed and swollen, usually related to a viral infection. Besides affecting facial muscles, the nerve affects tears, saliva, taste, and a small bone in the middle of the ear.
Viruses that have been linked to Bell's palsy include viruses that cause cold sores and genital herpes (herpes simplex), chickenpox and shingles (herpes zoster), infectious mononucleosis (the Epstein-Barr virus), cytomegalovirus infections, respiratory illnesses (adenoviruses), German measles (rubella), mumps, flu (influenza B), and hand-foot-and-mouth disease (a coxsackievirus).
Linked virus | Illness it causes |
Herpes simplex | Cold sores and genital herpes |
Herpes zoster | Chickenpox and shingles |
Epstein-Barr virus | Infectious mononucleosis |
Cytomegalovirus | Cytomegalovirus infections |
Adenoviruses | Respiratory illnesses |
Rubella virus | German measles |
Mumps virus | Mumps |
Influenza B | Flu |
Coxsackievirus | Hand-foot-and-mouth disease |
Who is most at risk for Bell's palsy?
Bell's palsy occurs more often in people who are pregnant, especially during the third trimester, or who are in the first week after giving birth; have an upper respiratory infection, such as the flu or a cold; have diabetes; have high blood pressure; or have obesity.
It is rare for Bell's palsy to come back. But when it does, there is often a family history of repeated attacks. This suggests that Bell's palsy might have something to do with genes.
Risk factor | What it means |
Pregnancy | More common during the third trimester or the first week after giving birth |
Upper respiratory infection | Having the flu or a cold raises the odds |
Diabetes | Increases risk |
High blood pressure | Increases risk |
Obesity | Increases risk |
Family history | Recurrence is rare, but repeated attacks often run in families, suggesting a genetic link |
What complications can Bell's palsy cause?
Mild symptoms of Bell's palsy typically disappear within a month. Recovery from more-complete facial paralysis can vary.
Complications may include irreversible damage to the facial nerve, and irregular regrowth of nerve fibers. This may result in involuntary contraction of certain muscles when you are trying to move other muscles, known as synkinesis. For example, when you smile, the eye on the affected side may close.
The most preventable complication involves the eye. Partial or complete blindness of the eye that will not close is possible. This is caused by excessive dryness and scratching of the clear protective covering of the eye, known as the cornea. Protecting and moisturizing the eye is one of the most important parts of self-care.
How is Bell's palsy diagnosed?
Bell's palsy has no specific test, so it is diagnosed mainly by examining facial muscle movement and ruling out other causes. Your health care professional looks at your face and asks you to move your facial muscles. You are asked to close your eyes, lift your brow, show your teeth, and frown, among other movements.
Other conditions, such as a stroke, infections, Lyme disease, inflammatory conditions, and tumors, can cause facial muscle weakness that mimics Bell's palsy. If the cause of your symptoms is not clear, your health care professional may recommend other tests.
Electromyography (EMG) can confirm the presence of nerve damage and determine how serious it is. An EMG measures the electrical activity of a muscle in response to stimulation. It also measures the nature and speed of the conduction of electrical impulses along a nerve.
Imaging scans may be needed on occasion to rule out other possible sources of pressure on the facial nerve, such as a tumor or skull fracture. These include magnetic resonance imaging (MRI) or computerized tomography (CT) scans.
There is no blood test for Bell's palsy. But blood tests can be used to rule out Lyme disease and other infections.
Diagnostic tool | What it does |
Physical exam | Clinician watches facial movements: closing eyes, lifting the brow, showing teeth, frowning |
Electromyography (EMG) | Confirms nerve damage and its severity by measuring electrical activity in the muscle and the speed of impulse conduction along the nerve |
MRI or CT scan | Rules out other sources of pressure on the facial nerve, such as a tumor or skull fracture |
Blood tests | No blood test exists for Bell's palsy; blood work rules out Lyme disease and other infections |
How is Bell's palsy treated?
Most people with Bell's palsy recover fully, with or without treatment. There is no one-size-fits-all treatment for Bell's palsy. But your health care professional may suggest medicines or physical therapy to help speed your recovery. Surgery is rarely an option for Bell's palsy.
Medicines
Corticosteroids, such as prednisone, are powerful anti-inflammatory agents. If they can reduce the swelling of the facial nerve, the nerve can fit more comfortably within the bony corridor that surrounds it. Corticosteroids may work best if they are started within several days of when symptoms start. Steroids started early improve the likelihood of complete recovery.
The role of antiviral drugs is not certain. Antivirals alone have shown no benefit compared with placebo. Antivirals added to steroids may benefit some people with Bell's palsy, but this is still not proved. Despite this, an antiviral medicine, such as valacyclovir or acyclovir, is sometimes given in combination with prednisone in people with severe facial palsy.
Physical therapy
Paralyzed muscles can shrink and shorten, which may be permanent. A physical therapist can teach you how to massage and exercise your facial muscles to help prevent this from occurring.
Surgery
In the past, decompression surgery was used to relieve the pressure on the facial nerve by opening the bony passage that the nerve passes through. Today, decompression surgery is not recommended. Facial nerve injury and permanent hearing loss are possible risks associated with this surgery.
Rarely, plastic surgery may be needed to correct lasting facial nerve problems. Facial reanimation surgery helps make the face look more even and may restore facial movement. Examples of this type of surgery include an eyebrow lift, an eyelid lift, facial implants, and nerve grafts. Some procedures, such as an eyebrow lift, may need to be repeated after several years.
Treatment | How it helps | Key points |
Corticosteroids (prednisone) | Reduces facial nerve swelling so it fits comfortably in the bony corridor | Works best if started within several days of symptom onset; early start improves likelihood of complete recovery |
Antiviral drugs (valacyclovir, acyclovir) | Sometimes added to prednisone in severe facial palsy | Antivirals alone showed no benefit versus placebo; benefit when added to steroids is not proved |
Physical therapy | Massage and exercises to keep paralyzed muscles from shrinking and shortening | Prevents possibly permanent muscle changes |
Facial reanimation surgery (rare) | Eyebrow lift, eyelid lift, facial implants, nerve grafts to even out the face and restore movement | For lasting problems; some procedures need repeating after several years |
Decompression surgery | Was used to open the bony passage | Not recommended today due to risk of facial nerve injury and permanent hearing loss |
How do you care for the eye on the affected side?
Because the eye on the affected side does not close, it is important to take steps to protect and care for that eye. This is the single most important self-care task during recovery.
Use lubricating eye drops during the day and an eye ointment at night to help keep your eye moist. Wear glasses or goggles during the day and an eye patch at night to protect your eye from getting poked or scratched. You may need to see a health care professional to monitor your eye.
During the day, you can also use your finger to close your eye repeatedly throughout the day. If your eye will not close completely, follow the routine above consistently until the eyelid works normally again.
What can you do at home for pain and comfort?
Home treatment may include taking pain relievers. Aspirin, ibuprofen, or acetaminophen are available without a prescription and may help ease your pain.
Applying moist heat may also help. Putting a washcloth soaked in warm water on your face several times a day may help relieve pain. Doing the massage and facial exercises recommended by your physical therapist may help relax your facial muscles.
What about alternative approaches?
Although there is little scientific evidence to support the use of alternative medicine to treat Bell's palsy, some people with the condition may benefit from the following.
Acupuncture places thin needles into specific points in the skin to help stimulate nerves and muscles, which may offer some relief. Biofeedback training teaches you to use your thoughts to control your body, which may help you gain better control over your facial muscles.
OnabotulinumtoxinA (Botox) may help manage symptoms such as facial spasms and tearing. Injections of onabotulinumtoxinA also may help improve the balance of the face.
How do you prepare for your appointment?
You may start by seeing your health care professional. You may be referred immediately to a doctor who specializes in the nervous system, known as a neurologist.
It is good to prepare for your appointment. Write down any symptoms you are experiencing, including any that may seem unrelated to the reason for which you scheduled the appointment. Write down key personal information, such as any major stresses or recent life changes. Make a list of all medicines, including dosages, and any vitamins or supplements you are taking. Take a family member or friend along, if possible, and write down questions you want to ask.
Questions to ask your health care professional include: What is the most likely cause of my symptoms? Are there other possible causes? What kinds of tests do I need? Is this condition likely temporary or long lasting? What treatments are available, and which do you recommend? Are there alternatives to the primary approach? I have other health conditions; how can I best manage these together? And do you have printed material or recommended websites?
Your health care professional is likely to ask questions such as: When did you begin having symptoms? Have your symptoms been continuous or occasional? How severe are your symptoms? What, if anything, improves or worsens them? Have any relatives ever had Bell's palsy or facial paralysis? Have you had symptoms of a more generalized infection?
What is the bottom line on Bell's palsy?
Bell's palsy is sudden weakness in the muscles on one side of the face, and it is one of the most frightening things to experience out of the blue. Half the face droops, the smile goes one-sided, and the eye on the affected side stays open. But the overall outlook is genuinely good: most people recover fully, with or without treatment, starting to improve within a few weeks and usually reaching complete recovery in about six months.
Because stroke can look the same, any sudden facial paralysis deserves immediate medical attention. Once a clinician confirms Bell's palsy, the treatment that matters most is a corticosteroid started early, ideally within several days of symptom onset, because early steroids improve the likelihood of complete recovery. Antivirals alone do not help, and decompression surgery is no longer recommended.
The other essential piece is eye care. An eye that cannot close can dry out and scratch the cornea, and in severe cases this can lead to partial or complete blindness of that eye. Drops by day, ointment and a patch by night, and glasses for protection are a simple routine that prevents the condition's most serious preventable harm.
If some weakness lingers, physical therapy keeps the facial muscles from shrinking, and a small set of surgical options exists for lasting problems. For most people, patience and protection carry them through to recovery.
Next steps: If you develop sudden facial weakness, seek emergency medical care immediately to rule out a stroke. Once Bell's palsy is diagnosed, ask about starting corticosteroids quickly, and begin the daily eye care routine described above.
FAQ
Is Bell's palsy the same as a stroke?
No. Bell's palsy is not caused by a stroke, but the symptoms are similar. Because any sudden facial paralysis could be a stroke, seek medical help right away and let a clinician determine the cause.
How long does Bell's palsy last?
Symptoms usually start to improve within a few weeks, and complete recovery typically happens in about six months. Mild symptoms often disappear within a month, while a small number of people keep some symptoms for life.
What is the best treatment for Bell's palsy?
There is no one-size-fits-all treatment, and most people recover fully with or without treatment. Corticosteroids such as prednisone are commonly used and work best when started within several days of symptom onset, as early steroids improve the likelihood of complete recovery.
Why can Bell's palsy cause blindness?
The eye on the affected side may not close, which can cause excessive dryness and scratching of the cornea, the clear protective covering of the eye. Daily lubricating drops, nighttime ointment, and eye protection prevent this complication.
Can Bell's palsy come back?
It is rare for Bell's palsy to recur. When it does, there is often a family history of repeated attacks, which suggests a possible genetic component.
Disclaimer: This article is for general informational purposes only and does not constitute medical advice. Always consult a qualified health care provider for individual questions.
References
Mayo Clinic Staff. Bell's palsy - Symptoms and causes. Mayo Clinic. March 15, 2024. https://www.mayoclinic.org/diseases-conditions/bells-palsy/symptoms-causes/syc-20370028
Mayo Clinic Staff. Bell's palsy - Diagnosis and treatment. Mayo Clinic. March 15, 2024. https://www.mayoclinic.org/diseases-conditions/bells-palsy/diagnosis-treatment/drc-20370034
Madhok VB, et al. Corticosteroids for Bell's palsy (idiopathic facial paralysis). Cochrane Database Syst Rev. 2016;7(7):CD001942. PMID 27428352. https://doi.org/10.1002/14651858.CD001942.pub5
Gagyor I, et al. Antiviral treatment for Bell's palsy (idiopathic facial paralysis). Cochrane Database Syst Rev. 2019;9(9):CD001869. PMID 31486071. https://doi.org/10.1002/14651858.CD001869.pub9
Baugh RF, et al. Clinical practice guideline: Bell's palsy. Otolaryngol Head Neck Surg. 2013;149(3 Suppl):S1-S27. PMID 24189771. https://doi.org/10.1177/0194599813505967
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