What Is Bell's Palsy?

Bell's palsy (BP) is a condition of facial paralysis that can be noticed with the weakness of muscles on one side of the face.

There are various reasons for facial paralysis that make it difficult to smile, frown, or even close the eye on the affected side. Sometimes it can result in loss of vision. It is mostly sudden in onset and goes away within a few days; however, in some cases, symptoms may persist longer.  Recurrent attacks of Bell’s palsy are uncommon; however, if it does occur, it is often associated with a family history. Some causes of Bell’s palsy include traumatised and inflamed facial nerves or viral infections.¹

This article explains all the aspects of Bell’s palsy for your better understanding.

Overview

BP is a sudden onset of facial muscle weakness. It usually affects only one side of the face where the facial nerve gets irritated. It can be a partial or complete loss of sensation, taste, salivation, and increased sensitivity to sound. The condition can be short-term or in some cases permanent.

Facial muscle weakness can result from various conditions such as

• Stroke
• Lyme disease
• Ramsay Hunt syndrome
• Inflammatory conditions like Sarcoidosis and vasculitis
• Some infections like tuberculosis or HIV
• Tumours in the mouth and face 

BP is the most common cause of unilateral (one-sided) facial paralysis. It is most commonly noticed in diabetic patients, pregnant people, and obese patients.² It is important to exclude these more serious conditions prior to giving treatment, so you should speak with a healthcare provider if you notice any symptoms. 

Causes of bell's palsy

Bell's palsy occurs when the facial nerve gets traumatised or inflamed. Due to the complex anatomy of the nerve and surrounding area, when it becomes inflamed it can damage the nerve. Nerves are responsible for muscle movement, so when a nerve is damaged it can result in palsy of facial muscles. 

Various reasons have been found to cause Bell's palsy

1. Trauma causing nerve compression
2. Any tumours in the head causing nerve compression
3. Viral infections like
   • Cold sores and genital herpes (herpes simplex virus)
   • Chickenpox and shingles (herpes zoster virus)
   • Infectious mononucleosis (Epstein-Barr virus) sometimes called glandular fever or mono
   • Cytomegalovirus infections
   • Respiratory illnesses (adenovirus)
   • German measles (rubella virus)
   • Mumps (mumps virus)
   • Flu (influenza B virus)
   • Hand, foot, and mouth disease (coxsackie virus)

Studies have also found that diabetic patients and those with pregnancy or post pregnancy have also experienced facial paralysis.^1,3

Signs and symptoms of bell's palsy

Facial paralysis due to Bell's palsy starts suddenly and progresses completely to one side of the face within 48-72 hours. Some may experience mild symptoms while others may experience a complete loss of sensation. The average age of onset is 40 years and affects both sexes equally. 

Common symptoms of BP are:³

• Facial drooping
• Drooling
• Facial pain
• Ear pain
• Sensitivity to sounds
• Inability to close eyelids
• Difficulty in speaking, eating, and drinking
• Headache
• Ringing in ears
• Loss of taste
• Difficulty making facial expressions
• Change in amount of tears
• Change in amount of saliva 

As the symptoms of Bell’s palsy are similar to that of a stroke, it is important to seek advice from a healthcare professional early. Stroke and massive nerve damage have to be suspected when:  

• Slow progressive (beyond 72 hours) facial palsy
• Recurrent episode of facial paralysis
• Prolonged episodes of paralysis (>4 months)
• Bilateral facial palsy
• Sudden complete facial paralysis⁴

Management and treatment for bell's palsy

Bell's palsy is self-limiting. The symptoms persist only for minor periods of time. The most common medications given to someone suffering from BP are:

1. Corticosteroids - are used to reduce inflammation in the nerve. Inflammation reduces the nerve and restores the normal functioning of nerve and muscle activity
2. Antivirals - most of the cases of Bell's palsy are due to viral infections. Antiviral medications have been found to reduce the symptoms of facial weakness
3. A combination of corticosteroids and antiviral therapy has been shown to settle symptoms faster
4. Supplemental care
   • Eyes - Facial paralysis can result in being unable to close your eyelids, which can lead to dry eyes. Therefore, as long as symptoms persist, you should use eye drops
   • Oral care - A reduction in saliva has been seen in BP patients. This results in an increase in bacteria and fungal infections. Artificial saliva has to be used until the normal secretion of saliva is restored

5. Physiotherapy or acupuncture can be used to restore the strength of facial muscles and increase nerve conductivity. Facial nerves can also be stimulated for better action.
6. Surgery
   • Nerve decompression surgery is needed in some cases to restore facial muscle weakness and hearing loss^3,4
   • Surgery is needed in some cases if muscle action is not restored. This can include plastic surgery to help with eyelid closure or smile correction

7. Botulinum injections can be used for restoring the aesthetic correction of facial muscles that have become non-functional. They can be used for facial asymmetry and facial tightness from BP^3,4 

Prognosis

BP usually subsides and is self-limiting. The symptoms gradually lessen within a few weeks. In general, BP subsides within 2-6 months. In some cases, it may take longer, and in others it may persist for longer periods(> 6 months).^4,5    

FAQs

How is bell's palsy diagnosed?

Your clinician may ask you to lift an eyebrow, frown, or smile to move facial muscles. If the muscles are not moving, you can suspect facial paralysis. To confirm the reason for facial paralysis, your doctor may exclude some of the conditions like Lyme disease, stroke, infections, inflammatory conditions, or tumours. They may also conduct blood tests, or electrical conduction tests like EMG to assess the functioning of nerve innervation to facial muscles. Electromyography (EMG) is a medical apparatus used to test for muscle activity like nerve innervation and speed of nerve conduction to a muscle.  Your doctor may conduct this test to know for the muscle weakness and defect in nerve conduction. Magnetic resonance imaging (MRI) and computed tomography (CT) may also be used to determine the cause of facial nerve inflammation. If hearing loss is suspected, audiography has to be used to assess the hearing function.

How can I prevent bell's palsy?

It is not clear what causes Bell’s palsy and there is no way to prevent it. BP is mostly due to a nerve injury or viral infections. In most cases, facial paralysis is temporary, however, symptoms can last longer. Whilst rare, Bell’s palsy can recur. It is important to speak with a healthcare professional if you experience any symptoms.  

Who is at risk of bell's palsy?

Bell's palsy is seen equally in both biological sexes. It is very rare prior to 15 years and post 45 years of age. People with diabetes and hypertensive patients were found to have a higher risk for BP. Pregnant individuals in the third trimester of pregnancy or immediately after the delivery are more prone to the occurrence of Bell's palsy. Patients who have an upper respiratory tract infection such as the flu or a cold, and patients who are obese are at a higher risk of developing Bell’s palsy.

How common is bell's palsy?

Bell’s palsy is a relatively common condition. It is found that 1 in 65 persons experience BP once in their lifetime and is one of the most common causes of one-sided facial palsy. 

When should I see a doctor?

Bell’s palsy is not a life-threatening condition; however, the symptoms are the same for some more serious conditions such as a stroke. Therefore, if you are experiencing symptoms, it is important to see a healthcare professional for a proper diagnosis. 

Summary

Bell’s palsy is a relatively common condition that can be caused by an infection or other condition. It is important to get your symptoms properly diagnosed by a healthcare professional so that you can be treated appropriately.  In most cases, the condition is transient, but some people experience complications like loss of sight. Most cases of facial paralysis are caused by Bell’s palsy, which is the result of viral infections. Otherwise, it might be a minor sign of a stroke. Therefore, one has to address the paralysis properly and get appropriate treatment. 

References

1. Eviston, Timothy J., et al. “Bell’s Palsy: Aetiology, Clinical Features and Multidisciplinary Care.” Journal of Neurology, Neurosurgery & Psychiatry, vol. 86, no. 12, Dec. 2015, pp. 1356–61. jnnp.bmj.com, https://doi.org/10.1136/jnnp-2014-309563.
2. Tiemstra, Jeffrey D., and Nandini Khatkhate. “Bell’s Palsy: Diagnosis and Management.” American Family Physician, vol. 76, no. 7, Oct. 2007, pp. 997–1002. www.aafp.org, https://www.aafp.org/pubs/afp/issues/2007/1001/p997.html.
3. Warner, Matthew J., et al. “Bell Palsy.” StatPearls, StatPearls Publishing, 2022. PubMed, http://www.ncbi.nlm.nih.gov/books/NBK482290/.
4. “Bell’s Palsy.” National Institute of Neurological Disorders and Stroke, https://www.ninds.nih.gov/health-information/disorders/bells-palsy. Accessed 4 Mar. 2023.
5. Baugh, Reginald F., et al. “Clinical Practice Guideline: Bell’s Palsy.” Otolaryngology–Head and Neck Surgery, vol. 149, no. S3, Nov. 2013. DOI.org (Crossref), https://doi.org/10.1177/0194599813505967.

This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Swathi Gadadasu

I am Dr Swathi G, from India, with experience as a dental clinician for 8 years, oral physician and Oral Maxillofacial Radiologist for 4 years, an academician for 3.5 years, an academic writer for 3 years and a medical writer for 1 year. With sound knowledge of clinical, non-clinical, scientific and academic and medical writing, working as a Freelancer Writer at Work foster. Due to my passion for writing, completed many national and international Publications in various indexed and well-known journals.

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