Facial weakness means not able to move one or both sides of face. It is usually one-sided resulting in facial asymmetry, but it can also involve both sides. It may cause significantly changed facial appearance and expressions, and the smile. Symmetry is eye-catching and attracts our gaze but the beauty is in asymmetry, if it is just about right. We generally assume that both sides of our body are equal and symmetrical. Paying close attention reveals subtle differences in size and details. A true smile is always beautiful, especially if it is tad asymmetrical.

Our facial expression, especially our smile, is our fundamental social tool that let us communicate without uttering a single word. Any hindrance of its use may create a significant social problem. There are many conditions that may cause weakness of one or both sides of our face.

What are the reasons for one-sided facial weakness?

One-sided facial weakness may happen due to damage to an area of the brain controlling facial movements (e.g., by stroke), or a problem with the nerve (the facial nerve) that connects brain to the facial muscles. There are multiple reasons for both locations.

How to differentiate if facial weakness is from a problem in the brain?

In most cases, if the problem is in the brain, weakness is of the lower part of the face and forehead muscles are mostly spared. So if facial weakness includes flatness of forehead, or inability to build forehead wrinkles on the affected side, it is likely not from brain. To make things complicated, in some cases of stroke forehead is involved, and in some cases of Bell’s palsy, forehead is not that much involved. One has to look at all the data, history and physical examination to find the exact location of the problem. In some cases, an MRI of brain is required.

What conditions of brain may cause facial weakness?

Common brain conditions that may cause facial weakness are a stroke, multiple sclerosis, infection (abscess), or a brain tumor.

What conditions of facial nerve may cause facial weakness?

Some common conditions affecting facial nerves are:

a. Infections: For example virus or Lyme disease.
b. Metabolic abnormalities: For example diabetes mellitus.
c. Inflammatory process: For example, sarcoidosis.
d. Stroke: Rarely.
e. Tumor: Even more rarely.

What conditions may cause facial weakness on both sides?

Condition of brain: Parkinson disease, and other Parkinsonian syndromes. Of note, strokes usually cause one-sided facial weakness.

Conditions of facial nerve: Lyme disease, immune dysfunction (Gillian-Bare syndrome). Also included is Mobius syndrome, a congenital condition with facial nerve paralysis on both sides.

Conditions of muscles: Myopathies, myasthenia gravis.

How is facial weakness treated?

It depends upon the cause.

What is Bell’s palsy?

It is one of the most common causes of one-sided facial weakness. It is caused by a problem with the facial nerve. It is not caused by a stroke in brain. Typically, facial weakness appears and worsens within 12-24 hours, and either plateaus or slowly improves in days to weeks. After 2-3 days, if weakness does not improve or if it gets worse, especially with treatment, it may not be Bell’s palsy.

What is the cause of Bell’s palsy?

The presumed cause is one of the common viruses, such as herpes simplex virus. There are many other viruses that may cause this condition, which may be a consideration in a different part of the world, e.g., chicken pox, mononucleosis, mumps, and polio. HIV virus may also cause this condition. There may be history of a cold or flu like illness a few weeks before developing Bell’s palsy. Generally speaking, unless there is an obvious alternate diagnosis, every case of Bell’s palsy is managed as it is from a viral infection.

Where is the problem in Bell’s palsy?

Facial nerve that carry messages from brain to the muscles of face pass thorough a convoluted course, which involves passing through a bony canal in temporal bone. This is the bottleneck area, with no room available for the nerve to swell in case it is infected or inflamed. The problem can be before, within, or after this bony canal, though the canal is usually involved.

What are the symptoms of Bell’s palsy?

Depending upon the exact location of inflammation, symptoms may include weakness of that side of face, sometimes also numbness, loss of sense of taste on that side of tongue, abnormal hearing (some noises may heard louder than normal), pain inside or behind the ear, and watering and irritation of the eye due to weakened or paralyzed blinking. Depending how bad the weakness is, patient may also have difficulty with chewing and sipping liquids.

How is Bell’s palsy diagnosed?

If there is history of a recent viral infection, and patient’s examination shows signs of a problem in the facial nerve and not in brain, as described above, and there is no other abnormality on examination, the diagnosis may be straightforward. Though an MRI of brain may reveal abnormal signal in the facial nerve, it is not needed to make this diagnosis. It can be considered if an alternate diagnosis is suspected.

Is it necessary to have a test to find the exact virus causing Bell’s palsy?

In most cases, this type of testing is not needed, and not performed. This is because the patient may still be treated in the same manner. Unlike a bacterial infection when we like to find out the exact bacteria involved, so that we may use a specific antibiotic, we lack specific medicines for most viruses. On the plus side, most virus illnesses do not require any specific treatment as body’s immune system kicks in and takes care of it. The problem occurs when a common virus like herpes affects some critical organ like a nerve. The body may still be able to build an immune response, but without any treatment there may already be permanent injury to the nerve before that happens. This is the reason that every case of Bell’s palsy is treated right away to prevent permanent nerve injury.

How is Bell’s palsy treated?

Two medicines are routinely used, and they shall be taken right away: a steroid, such as prednisone (which acts as a strong anti-inflammatory drug), and an anti-viral drug, such as acyclovir or valacyclovir. Both are used together for about 10 days. Sometimes a pain medicine is needed for ear pain or headache.

If patient is unable to completely close the affected eye, proper eye care is required. Blinking has an important function to protect our eyes, specifically the cornea. Every blink coats the cornea with a thin layer of fluid to prevent it from drying. Without this coating, cornea can quickly get dry, which may cause irritation, watering, pain, and even visual impairment. Artificial eye drops, which are a formulated liquid, used every few hours, can provide some relief. In addition, the eye shall be closed shut, taped and patched, especially during sleep to avoid drying from long-term exposure. Even with a weakened blink, sunglasses or some type of protective glasses can help to avoid any direct hit to the cornea.

In most cases, abnormalities of hearing and taste are not severe enough to warrant any particular treatment, and usually do not last long. Care and caution is advised for any difficulty swallowing due to weakness of facial muscles.

Other than medical treatment, some physical measures may also help. To stimulate the facial nerve, certain exercises may help. Try to whistle, which may not be possible in initial stages but keep trying. Try to inflate a rubber balloon. Physical therapists also try electric-shock therapy, though its benefit is debatable.

Psychological toll of changed facial appearance may result in significant anxiety and depression. It is treated with education, counseling, and sometimes medicines.

How effective is the treatment for Bell’s palsy?

It is reasonably effective but the response may depend upon three factors: If it is started ASAP, or at least within first 24 hours, severity of nerve injury, and if the diagnosis is correct. If it is not Bell’s palsy, or if it does not involve inflammation, this medical treatment may not help. My experience is that it works in 80-90% of the time, and when it works, it resolves 80-90% of weakness. Nobody complains if it works even better. Facial nerve has about 10,000 neurons. Bell’s palsy may damage hundreds or thousands of them, and some may be permanently lost.

How is the Bell’s palsy from Lyme disease is treated?

If there is strong suspicion of Lyme disease, or the Lyme test is positive, an antibiotic is added to the drug regimen. Presently, it is Doxycycline for 2-3 weeks.

How long it takes for the treatment of Bell’s palsy to work?

In a typical case, patient may start noticing an improvement in 1-3 weeks; full possible recovery may take 3-6 months.

What if treatment with medicines (steroids and antiviral drug) does not make any difference?

Provided the treatment is started right away, if it does not make any difference in 2-3 weeks, or if the situation worsens, alternate reason needs to be explored. On the other hand, if treatment is started after 24-48 hours, there may already be significant permanent damage and improvement may not be as expected.

Is there a need for a repeat course of medicines if the first course does not make any difference?

Because this approach has not been tested, the best answer to this question is, we do not know. It seems unlikely that another course of same medicines can make significant difference.

Is there a surgical treatment for Bell’s palsy?

Not in Bell’s palsy. It may be an option for patients who have a tumor, abscess, or another mass affecting the nerve.

I had Bell’s palsy; why my eye keeps on shutting itself?

This phenomenon is called aberrant regeneration of a nerve. As stated above, facial nerve has about 10,000 neurons, and inflammation may damage hundreds to thousands of them. Once inflammation is controlled, neurons start to heal and try to reach their other damaged ends. But not all succeed, and in this process some end up joining a different neuron. This creates an abnormal circuitry resulting in the type of problem described above. It is a sign of healing, and not a sign of further damage. In most cases, no intervention is needed. In some more severe cases, treatment with Botox may be an option.

I had Bell’s palsy; can I have it again?

In less than 10% of patients with Bell’s palsy, it may happen again. Every attack is separately evaluated, and managed accordingly.

I suffered from Bell’s palsy; can I have flu shot?

Yes. In fact having a flu shot help us protect ourselves from certain viral infections, which may decrease chances of having Bell’s palsy.

What should I do if I develop facial weakness?

If it is within 12 hours, call 911 or go to ER right away to make sure it is not a stroke. This is because if it is a stroke, it can only be treated within first few hours. If it is after that, consider talking to your PCP. You have to see a physician right away or at least that day. Two decisions have to be made right away: a. the correct diagnosis, and b. its treatment.

Is Bell’s palsy a genetic disorder?

Not really, but some families might be more prone to certain viral infections increasing their risk.

What if Bell’s palsy is caused by diabetes?

First, there is no definite test we have that may confirm that it is definitely caused by diabetes. It is a matter of association. If a patient with diabetes has no history of a recent viral infection, and diabetes is particularly not well controlled, it is likely that diabetes has a role in it. In any case, even with diabetes, it is better to treat with a short course of prednisone and an antiviral drug. The response to treatment may not be as good as without uncontrolled diabetes. Generally speaking, we do not treat diabetic neuropathy with steroids, but Bell’s palsy may be an exception. Without a definite test to disprove a viral etiology, and to avoid complication of permanent facial nerve injury, we make the decision to treat.

When is MRI needed in case of facial weakness, or Bell’s palsy?

MRI is not indicated in routine cases of Bell’s palsy. Interestingly, patients who show up in emergency room, almost always have a CT scan, which does not help either. Imaging is indicated if an alternate diagnosis is suspected, such as a stroke or tumor. In case of a stroke, the pattern of facial weakness is different; and in case of a tumor, patient may have more than just facial weakness. If imaging is needed, an MRI brain with and without contrast is done; CT scan does not provide enough details.

Where can I get more information about Bell’s palsy?

American Academy of Neurology
American Otolaryngology Society