Bell’s Palsy: Causes, Symptoms, Diagnosis, & Treatment

What is Bell’s Palsy?

Bell’s palsy is a condition that causes paralysis or temporary weakness of the facial muscles. This facial palsy occurs when the nerve that controls your facial muscles becomes swollen, compressed, or inflamed.

This condition causes half of your face to appear to droop or become stiff. Smiles are one-sided smiles, and your affected side’s eye resists closing.

Bell’s palsy is also called acute peripheral facial palsy of unknown cause. This condition can appear in the space of a few hours and in most cases, its symptoms usually disappear within a few weeks without treatment.

Bell’s palsy is caused by some kind of trauma to the facial nerve (seventh cranial nerve). It can occur at any age but is most prevalent between the ages of 16 and 60. Bell’s palsy is named after Charles Bell. He was a Scottish anatomist who first described this condition.

What are The Symptoms of Bell’s Palsy?

Signs and symptoms of Bell’s palsy appear suddenly and the person who develops this condition may notice the following symptoms (1):

  • Sudden weakness or paralysis on one side of your face — occurring within hours to days
  • Difficulty in closing the lip, eye, or both on the affected side
  • Drooling from one side of the mouth
  • Facial pain
  • Change in the sense of taste
  • Increased sensitivity to sound on the affected side (sounds appear much louder than normal in the days before you notice any symptoms).
  • Facial drooping and difficulty making facial expressions, such as smiling or closing your eye
  • Changes in the amount of tears your eye produces
  • Pain around the jaw or behind or in the ear on the affected side
  • Irritation of the eye on the affected side
  • You find it hard to talk
  • Have trouble drinking and eating

Rarely, Bell’s palsy can affect the nerves on both sides of your face.

Research has shown that symptoms of Bell’s palsy tend to appear and progress over 72 hours (1) or so, after which they stabilize. Once symptoms appear, they generally get better over the next 3 weeks or so.

In most of the cases (about 80%) symptoms resolve within 3 to 6 months. But in some cases, people who get Bell’s palsy have a longer recovery period and rarely, they may have some permanent symptoms.

What are the Causes of Bell’s Palsy? 

Bell’s palsy occurs due to the swelling or compression of the seventh cranial nerve, leading to facial weakness or paralysis. The exact cause of this nerve damage isn’t clear, but many medical researchers (2) believe that it is most likely triggered by a viral infection.

Viruses that are believed to trigger Bell’s palsy include:

  • Flu (influenza)
  • German measles (rubella)
  • Chickenpox and shingles (herpes zoster)
  • Cytomegalovirus infections
  • Cold sores and genital herpes (herpes simplex)
  • Infectious mononucleosis (Epstein-Barr)
  • Respiratory illnesses (adenovirus)
  • Mumps (mumps virus)
  • Hand-foot-and-mouth disease (coxsackievirus)

The nerve that controls facial muscles (the seventh cranial nerve) passes through a narrow corridor of bone on its way to the face. In Bell’s palsy, this cranial nerve becomes swollen and inflamed, which is usually linked to a viral infection. Along with facial muscles, this nerve also affects saliva, tears, taste, and a small bone in the middle of your ear.

Causes of The Seventh Cranial Nerve Palsy

Often, there is no clear reason why Bell’s palsy occurs, but the seventh cranial (or facial) nerve palsy is also associated with:

  • Injury
  • Diabetes
  • Lyme disease
  • Sarcoidosis
  • Multiple sclerosis
  • Guillain-Barré syndrome
  • HIV
  • Tuberculosis
  • Myasthenia gravis
  • A tumor
  • Vasculitis

If you are diagnosed with one of these conditions, then the doctor will treat the underlying cause.

Diagnosis of Bell’s Palsy

A person having Bell’s palsy may get benefit from treatment, if it starts within 72 hours of the appearance of symptoms, so it is best to take medical help as soon as possible.

Your physician will do a physical examination to determine the extent of weakness in your facial muscles. He/she will look at your face and ask you to move your facial muscles by lifting your brow, closing your eyes, showing your teeth, and frowning, among other movements.

The physician will also inquire about your symptoms, including when they began and when you first became aware of them.

While there is no particular lab test that your doctor may perform to confirm that you have Bell’s palsy, he or she can utilize a range of tests to aid in the diagnosis of this condition. These tests can also rule out other probable causes of facial weakness, such as Lyme disease or Guillain-Barré syndrome, which may require treatment.

Tests for Bell’s Palsy

The tests for Bell’s palsy may include the following:

Blood Tests

There is no specific blood test for Bell’s palsy. But blood tests can be used to rule out:

  • The presence of a bacterial or viral infection
  • Diabetes or other conditions

Lumbar Puncture

To confirm the diagnosis of Lyme disease, if it is suspected.

Imaging Tests

Imaging tests such as Magnetic resonance imaging (MRI) or computerized tomography (CT) may be needed to rule out other possible sources of pressure on the facial nerve, such as a skull fracture or a brain tumor.

Electromyography (EMG) Test

In an electromyography (EMG) test, a doctor inserts extremely thin wire electrodes into a muscle to measure the electrical activity of the muscle in response to stimulation.

EMG also measures the speed and nature of the conduction of electrical impulses along a nerve. This test is used to:

  • Check whether the nerves that control the facial muscles have been damaged, and
  • Determine the extent of the damage

What Are The Risk factors For Bell’s Palsy?

Certain conditions and factors may increase your risk of Bell’s palsy, among them are:

  • Diabetes
  • Pregnancy (pregnant woman who is especially in the third trimester, or who is in the first week after giving birth)
  • Obesity
  • Upper respiratory infection (people who have an upper respiratory infection such as a cold or the flu)

Recurrent Bell’s palsy attacks are uncommon. When they do happen again, then there’s generally a family history of recurrent attacks. This shows that Bell’s palsy may have a link with your genes.

A study conducted in 2019 suggests that patients with migraine may have a higher risk of Bell’s palsy, especially if they are in the age group of 30 to 60 years (3).

What is the Treatment of Bell’s Palsy?

With or without treatment, most persons with Bell’s palsy recover completely. Bell’s palsy has no one-size-fits-all (i.e. suitable for all patients) treatment. However, your doctor may prescribe drugs or physical therapy to fasten your recuperation. Rarely surgery is required to treat Bell’s palsy.

Care of the Eye On The Affected Side

It is very important to take some steps to safeguard and care for the eye on the affected side, as it doesn’t close.  For this:

  • Keep your eyes moist by using lubricating eye drops during the day and an eye ointment at night.
  • Protect your eye from being poked or scratched by wearing glasses or goggles during the day and an eye patch at night, if possible.
  • An eye doctor consultation may be needed to check the eye in severe cases of Bell’s palsy.

Medications For Bell’s Palsy

Bell’s palsy is generally treated with the following medications:


Corticosteroids, like prednisone, are strong anti-inflammatory agents that help in decreasing nerve swelling, and may also help you recover facial movement faster. The nerve will fit more easily within the bone corridor around it if the swelling of the facial nerve is reduced.

Treatment with corticosteroids is most effective if you start them within 48 hours of noticing your symptoms. Early use of steroids in the treatment of Bell’s palsy can increase the chances of complete recovery.

Antiviral Drugs

Antiviral drugs may speed recovery, but how much benefit they provide is yet unclear. When compared to a placebo, antivirals haven’t shown any benefit. Some persons with Bell’s palsy may benefit from antivirals combined with steroids, but this has yet to be proven.

In spite of this, for those with severe facial palsy, an antiviral drug such as acyclovir or valacyclovir is used along with prednisone.

Physical therapy

Muscles that have been paralyzed may shrink and shorten, which can be irreversible. To help avoid this, a physical therapist can teach you how to massage and exercise your facial muscles. These facial exercises help in strengthening your facial muscles and recovering facial coordination.


If a person with Bell’s palsy does not improve within a few weeks or months, then surgery may be required.

Surgery can help in:

  • Improving facial appearance
  • Preventing dry eyes
  • Reducing pressure on the nerve

Decompression Surgery

Decompression surgery was previously used to relieve pressure on the facial nerve by opening the bony channel through which the nerve passes. But today, decompression surgery is very rarely performed, because it carries the risk of permanent facial nerve damage and lifelong hearing loss.

Facial Plastic Surgery

Facial plastic surgery may be required for people who don’t recover and help to correct facial asymmetry and assist with eyelid closure.

This surgery can improve the appearance of the face and restore facial movement. An eyelid lift, an eyebrow lift, facial implants, and nerve grafts are examples of facial reanimation surgery.

After some years, some surgical procedures, like an eyebrow lift, may need to be repeated.

Home Remedies or Home Treatment For Bell’s Palsy

Treatment at home might include:

Pain Relievers

Without a prescription, ibuprofen, aspirin, or acetaminophen can help relieve pain.

Mouth Hygiene

You should carefully brush and floss your teeth, and have regular dental checkups, because food particles can build up along with other problems, due to a lack of sensation in the mouth.

Practice Some Physical Exercises

Your physical therapist may recommend massaging and exercising your face to assist relax your facial muscles.

Alternative Medicine

There is little scientific evidence, which supports the use of alternative medicine in the treatment of Bell’s palsy, but some people may get benefit from the use of these alternative therapies. These may include:


Acupuncture is a treatment, in which thin needles are inserted into the skin to stimulate specific points in the body. Its goal is to provide relief from a health condition or a symptom, like pain.

Biofeedback Training

Biofeedback training can help you achieve better control over your facial muscles by teaching you to utilize your thoughts to regulate your body.

Botulinum Toxins

Botulinum toxin may help with symptoms including facial spasms and tearing.

There is some evidence that injection of botulinum toxin type A (also known as Botox), may help to restore facial symmetry (4). But it is important to apply this treatment precisely; otherwise, it may result in reduced function and an increased appearance of paralysis.

What are the Complications of Bell’s Palsy?

In a mild case of Bell’s palsy, symptoms usually go within a month. But in severe cases, where the face was totally paralyzed, recovery time may vary and complications may occur.

Possible complications of Bell’s palsy include:

Irreversible Facial (or Seventh Cranial) Nerve Damage

Irreversible damage to your facial (or seventh cranial) nerve that controls your facial muscles

Nerve Fibers’ Irregular Regrowth

This Irregular regrowth of nerve fibers may lead to involuntary contraction of certain muscles when you’re trying to move other muscles (a condition called synkinesis).  For example, your eye on the affected side may close when you smile.

Partial or Complete Blindness of the Eye on the Affected Side

Excessive dryness and scratching of the clear protective covering (cornea) of the eye can lead to eye infections, ulcers, or even vision loss.

How Can You Prevent Bell’s Palsy?

Presently, there isn’t any known way to prevent Bell’s palsy, because it is probably triggered by a viral infection (2).

Generally, you will get Bell’s palsy only once, but it can sometimes come back. This is more likely if you have a family history of recurrent attacks of this condition.

What is the Outlook (prognosis ) for people who have Bell’s Palsy?

The outlook for the majority of people with Bell’s palsy is good. Full recovery can take two to six months, depending on the severity of nerve damage.

If the nerve damage is mild, you will start noticing a gradual lessening of symptoms within 2 to 3 weeks. But if the nerve damage is more severe, it can take 3 to 6 months to see an improvement. Rarely, some symptoms may continue to return or some people never fully recover.

You should immediately contact your doctor if you have symptoms of Bell’s palsy. Prompt treatment can help in fast recovery and may prevent any complications.



1) Bell Palsy

2) Bell’s Palsy Fact Sheet

3) Increased risk of Bell palsy in patients with migraine

4) Botulinum Toxin Type A to Improve Facial Symmetry in Facial Palsy: A Practical Guideline and Clinical Experience



This article is intended for informational purposes only. Any information associated with this article should not be considered as a substitute for prescriptions suggested by local health care professionals.


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