Bell’s palsy is characterised by the paralysis of the muscles on one side of the face — usually due to inflammation or compression of the facial nerves. It often has an acute onset but is temporary in duration, causing facial asymmetry such as drooping on one side or difficulty closing one eye.
Common symptoms of Bell’s palsy include drooping of one side of the face, typically seen on the lips.
What is Bell’s palsy?
Bell’s palsy is a neurological condition that affects the 7th cranial nerve (CN VII), also known as the facial nerve, which is responsible for [1]:
Facial movements
Tear and saliva production
Taste sensations
Ear muscle functions
Paralysis on this nerve causes one side of the face, either the left or the right, to become weak and droop, which is a characteristic symptom of Bell’s palsy. It is often an acute onset and usually self limiting.
Signs and symptoms of Bell’s palsy
Bell’s palsy is mostly temporary, with the onset of symptoms as early as several hours to 3 days. Common symptoms of Bell’s palsy are:
Weakness and paralysis of one side of the face
Drooping of the affected side, usually of the eyebrow, eyelid, and mouth
Drooling from the side of the mouth
Eye dryness on the affected side
Pain around the jaw or the ear
Headache
Loss of taste
Ringing in the ear (tinnitus)
Increased sensitivity to sound on the affected side
Bell’s palsy vs Stroke
Facial paralysis and drooping is also a common indicator of stroke. However, unlike Bell’s palsy, stroke is a severe condition and immediate medical attention is necessary. Here are the key differences to identifying a stroke from a case of Bell’s palsy:
Bell’s Palsy
Stroke
Cause
Temporary paralysis of facial nerves
Blockage (ischaemic) or rupture (haemorrhaging) of a blood vessel in the brain
Key symptoms
Weakness and numbness of one side of the faceEye drynessDroolingOnly limited to the face/headDoes not affect cognitive abilities (thinking, language)
Sudden numbness or weakness of one side of the body – may involve arms and legsVision problemsConfusionTrouble speaking or understanding languageSeizures Loss of balance and coordination
If you suspect you or a loved one is experiencing a stroke instead of Bell’s palsy, contact emergency services as soon as possible.
What causes Bell’s palsy?
Bell’s palsy is caused by inflammation to the facial nerves that control the face, which leads to the dysfunction and paralysis of the nerve [2]. Scientists are not entirely sure what causes this inflammation, but several possible causes include:
Facial nerve compression — Compression of the facial nerve within the labyrinthine segment of the nerve [3]
Viral infections — Viral infections, such as varicella zoster virus (chicken pox), herpes simplex virus (cold sores), Epstein-Barr virus, or common flu viruses [2]. These viruses are thought to infect the axons of the nerve, which leads to axonal degradation eventually leading to dysfunction of the nerve [1].
Herpes simplex virus (HSV-1) (cold sores)
Varicella-zoster virus (chicken pox/shingles)
Epstein-Barr virus (mononucleosis)
Influenza, COVID-19, and other viral illnesses
In rare cases, Bell’s palsy can affect both sides of the face, this is called bilateral Bell’s palsy, as opposed to unilateral Bell’s palsy [4].
Inflammation to the facial nerves cause the symptoms of Bell’s palsy.
Risk factors of Bell’s palsy
Bell’s palsy can affect anyone, however several risk factors can increase the chances of Bell’s palsy:
Pregnancy – Incidences of Bell’s palsy in pregnant women are commonly reported in the third trimester, as well as 2 weeks postpartum. Cases of Bell’s palsy in pregnant patients are more severe, some patients develop complete facial paralysis and do not recover fully [5]. Pregnant women are also likely to develop preeclampsia, which is also a risk factor for Bell’s palsy.
Preeclampsia – Preeclampsia is a hypertensive disorder causing high blood pressure that occurs during pregnancy, it is a known risk factor for Bell’s palsy [6].
High blood pressure – Hypertension or high blood pressure is a risk factor of Bell’s palsy likely due to compression of the blood vessels on the facial nerve, causing paralysis [6].
Diabetes – Similar to high blood pressure, diabetes is thought to cause Bell’s palsy via compression of the facial nerve by blood vessels [7].
Obesity – Obesity is also a risk factor for Bell’s palsy, likely due to the increased risk for hypertension and diabetes [6].
Viral infections – Viral infections, typically of HSV-1, increase the risk of inflammation of the nerves [1, 8, 9].
Diagnosis of Bell’s palsy
Diagnosis of Bell’s palsy is typically done by ruling out other causes of facial paralysis. The first step when consulting a neurologist will be to assess and evaluate your symptoms and medical history. Your neurologist will diagnose you based on the following:
Medical history – Taking your medical history is important to know whether you may have any viral infections or non-communicable diseases (e.g. diabetes, hypertension) that may cause Bell’s palsy. Clinicians also may ask whether you may be exposed to other pathogens that can cause facial paralysis, such as Lyme disease [1, 8].
Blood test – Blood tests can be used to look for viral infections or measure blood sugar levels. It can also be used to rule out other causes such as Lyme disease.
Imaging test – Imaging tests such as magnetic resonance imaging (MRI) can be used to identify abnormal structures in the brain, such as strokes, tumours, or bone fractures that may cause facial paralysis.
Electromyography (EMG)– An EMG test is typically ordered to assess nerve damage and stimulation. This can also help predict how soon you can recover.
Despite being a relatively mild condition, Bell’s palsy should be properly diagnosed by a medical professional to rule out other more serious conditions with similar symptoms.
Treatment of Bell’s palsy
Bell’s palsy typically resolves on its own. Between 70 to 80% of patients with Bell’s palsy recover fully without treatment [8]. However, treatment can be given to reduce recovery time and risk of complications. Common treatments prescribed include:
Corticosteroids – Corticosteroids are used to reduce inflammation of the nerve, prednisone or prednisolone are commonly prescribed for patients with Bell’s palsy 72 hours after onset of facial paralysis. Use of corticosteroids also improves recovery of motor function of the face [9].
Antiviral medications – In the case that Bell’s palsy is caused by a viral infection, doctors usually prescribe antiviral medications to treat the infection. Common antiviral agents prescribed in Bell’s palsy cases are acyclovir and valacyclovir. Antiviral agents are also used together with corticosteroids.
Eye care – Eye care is important as the lack of tear production can lead to dry eyes. Prolonged dryness in the eyes can lead to irritation, keratitis, ulceration, and eventually vision problems. Protecting the eyes can be done by applying eye drops and ointments, or taping the eye shut while sleeping [8].
Physiotherapy – Facial retraining can be recommended for patients with incomplete recovery to regain motor functions.
Acupuncture – Acupuncture may support recovery in Bell’s palsy by improving blood flow, reducing inflammation, and stimulating nerve regeneration. When started early, it can enhance facial muscle function and complement medical treatment.
Surgery – in some cases, surgery may be necessary to decompress the facial nerve. However, this is only reserved for patients with severe loss of function and is not the recommended treatment modality for most cases of Bell’s palsy [8].
When does Bell’s palsy need treatment?
It is important to seek medical treatment as soon as you experience muscle weakness in your face. Bell’s palsy should generally resolve within 6 to 8 weeks, but can take up to 3 to 6 months to return to normal in some cases.
Complications of Bell’s palsy
Although typically self-resolving, Bell’s palsy can also develop complications such as:
Loss of facial nerve function – Prolonged nerve inflammation can lead to permanent damage to the nerves.
Synkinesis (simultaneous involuntary movements) – Irregular or abnormal regrowth of the nerve fibres may cause involuntary motions when doing voluntary movements. For example, the eye on the affected side may close when you smile.
Partial or complete blindness – Severe dry eyes can lead to scratching of the cornea, the cornea is the transparent layer that protects the iris and pupils, damage to the cornea may lead to vision problems.
Consulting a doctor is important to reduce the risks of these complications.
Summary
Generally, Bell’s palsy resolves on its own, especially in milder cases. In fact, most people fully recover within a few weeks to a few months. However, consulting a doctor can help you get treatment to speed up your recovery and achieve better outcomes. Most importantly, it helps you rule out other, more serious conditions that can cause similar facial paralysis symptoms, such as a stroke, brain tumour or multiple sclerosis.
Schedule a consultation with us today for a detailed assessment and a personalised treatment plan.
Frequently Asked Questions
How long will Bell’s palsy last?
Most cases of Bell’s palsy resolve in 6 to 8 weeks, some patients may experience longer recovery times.
Is Bell’s palsy a serious condition?
Bell’s palsy is considered a mild condition, but it can be similar to other more serious conditions of facial paralysis. Some cases of Bell’s palsy may also not recover fully or end up with complications after recovery. Hence visiting a doctor is always recommended to get a proper diagnosis and treatment.
How can I prevent Bell’s palsy?
Unfortunately there is no way of knowing whether you will get Bell’s palsy and how to prevent it. Risks can be reduced by managing common risk factors such as hypertension, diabetes, and obesity.
Is Bell’s palsy permanent?
Bell’s palsy is generally a temporary condition, however, in cases of severe nerve damage, it can lead to permanent facial weakness or cause residual effects. Cases of recurrences may also happen.
What to avoid with Bell’s palsy?
When experiencing Bell’s palsy, it is important to avoid stress as it can further trigger inflammation of the nerves. Stimulants such as caffeine and alcohol should ideally be avoided as well.
Is Bell’s palsy a mini stroke?
No, Bell’s palsy and stroke are different conditions with different causes. Although both conditions can look similar, Bell’s palsy is caused by inflammation and paralysis of the facial nerve, while stroke is caused by ischaemia or haemorrhage of the blood vessels in the brain. Bell’s palsy is also typically mild, while a stroke can be life-threatening if not treated immediately.
Is Bell’s palsy caused by stress?
Stress can contribute to Bell’s palsy as stress can contribute to a weakened immune system and inflammation, which can trigger Bell’s palsy.
Does your face go back to normal after Bell’s palsy?
Yes, most cases of Bell’s palsy are mild and self-resolving, and your face can return to normal. However, chronic and recurrent cases of Bell’s palsy may lead to gradual facial paralysis as the nerves are constantly damaged from inflammation. To avoid nerve damage and subsequent facial paralysis, visit a neurology clinic if you experience chronic or recurring Bell’s palsy.
What are the signs that Bell’s palsy is getting better?
Typically, Bell’s palsy can resolve on its own in about 6 to 8 weeks, common signs include being able to feel sensations from the affected side, improved facial expressions, and facial tingling. Gradually, you will be able to close your eyes or lift your eyebrows, involuntary movements may occur occasionally during the recovery phase.
What exercises are good for Bell’s palsy?
Facial exercises and physical therapy can benefit those with Bell’s palsy to regain muscle strength. It is important to note that recovery for Bell’s palsy may differ from each patient, hence the type of exercises may also differ from patient to patient, follow your doctor’s instructions on the type of exercises recommended for you.
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