Bell Palsy

What Bell palsy is

Bell palsy is an acute problem with the facial nerve, also called cranial nerve VII. This nerve controls most muscles of facial expression. It also contributes to eyelid closure, taste on the front part of the tongue, tear production, and control of a small muscle that softens loud sounds. When the nerve becomes inflamed or compressed along its narrow path through the skull, one side of the face may become weak.

The term Bell palsy is used for an otherwise unexplained, rapid-onset peripheral facial nerve palsy. It is a diagnosis of exclusion, which means a clinician first considers conditions that can look similar. Stroke, Lyme disease, shingles involving the ear, middle-ear or mastoid infection, trauma, tumors, autoimmune conditions, and other neurologic disorders can all cause facial weakness. Treatment and urgency differ, so the label should not be applied from appearance alone.

Bell palsy is not the same as weakness caused by damage to the facial muscles themselves. It is also not contagious. Although viral reactivation is one proposed trigger, a person does not usually receive a test showing one definite virus caused their episode.

Symptoms and typical course

Weakness usually develops over several hours and reaches its greatest severity within about three days. The forehead, eyelid, cheek, and mouth on one side can all be affected. A person may have trouble raising an eyebrow, closing one eye, smiling evenly, keeping food or liquid inside the mouth, or pronouncing certain sounds. Saliva may leak from the weak corner of the mouth.

Other symptoms can include pain around the ear or jaw, altered taste, a feeling of facial numbness despite preserved skin sensation, dry eye, excessive tearing, or unusual sensitivity to sound on the affected side. Ear pain and sound sensitivity can occur in Bell palsy, but a blistering rash in or around the ear, severe vertigo, or hearing loss may suggest another condition and should be reported promptly.

Many people begin to improve within a few weeks and recover substantially within several months. Recovery is less predictable when paralysis is complete, treatment is delayed, the person is older, or there are other medical factors. Nerve healing can be slow. Persistent effects may include weakness, facial tightness, muscle contracture, crocodile tears while eating, or synkinesis, in which one facial movement triggers another, such as the eye narrowing during a smile.

Treat a new facial droop as urgent

Call emergency services for a sudden facial droop accompanied by arm or leg weakness, numbness, trouble speaking, confusion, severe imbalance, sudden vision change, a new severe headache, loss of consciousness, or a seizure. Note the last time the person was known to be normal. Do not wait to see whether the symptoms improve and do not drive the person if emergency transport is available.

Stroke can sometimes affect facial movement differently from Bell palsy, but forehead movement is not a safe home rule-out. Some strokes can mimic a peripheral facial palsy, and people may overlook subtle limb, speech, or coordination changes. A clinician needs to interpret the complete neurologic examination and the timing.

Same-day assessment is also important for any new isolated facial weakness because early treatment for Bell palsy has a limited time window and alternative causes may need urgent care. Seek prompt attention for inability to close the eye, eye pain, redness, light sensitivity, reduced vision, ear blisters, fever, severe headache, facial swelling, weakness on both sides, progressive symptoms beyond several days, or weakness that returns.

Possible causes and risk patterns

The exact cause is often unknown. Researchers think inflammation and swelling of the facial nerve may follow reactivation of a virus that has remained inactive in nerve tissue. This is a biologic explanation under study, not evidence that a person can spread Bell palsy to others.

Bell palsy can occur at any age. It is reported more often during pregnancy, particularly later in pregnancy or soon after delivery, and in people with diabetes, upper respiratory illness, obesity, or high blood pressure. These associations do not prove the cause in an individual. A person without any known risk factor can still develop it.

Recurrent facial palsy is unusual and warrants a fresh evaluation. Family history, repeated episodes on the same side, slowly progressive weakness, facial twitching before weakness, hearing changes, or other cranial nerve findings may lead a clinician to look more carefully for a structural, inflammatory, infectious, or genetic explanation.

How clinicians make the diagnosis

The clinician asks exactly when weakness began, how quickly it progressed, and whether there are speech, swallowing, limb, balance, vision, hearing, rash, tick-exposure, injury, or systemic symptoms. They review pregnancy, diabetes, immune status, recent infection, travel, medicines, and prior episodes. The examination checks the entire face and also assesses eye movements, speech, strength, sensation, coordination, gait, ears, skin, and other cranial nerves.

A classic, isolated, rapidly developing one-sided peripheral facial weakness may not require extensive testing. Testing is guided by atypical findings. Blood tests may be used when Lyme disease, diabetes, infection, or another systemic cause is plausible. Imaging may be considered for gradual onset, recurrent or persistent symptoms, additional neurologic findings, trauma, suspected tumor, or an uncertain diagnosis. Electrical nerve tests are sometimes used in severe cases to estimate nerve injury and prognosis.

Do not rely on a mirror test, phone application, or video consultation alone when symptoms are new and stroke has not been excluded. A recorded video can help document onset and progression, but it does not replace timely assessment.

Treatment and early priorities

For adults with a typical new Bell palsy, clinicians commonly prescribe an oral corticosteroid. Evidence supports the greatest benefit when treatment starts within 72 hours. Steroids have important considerations, including blood glucose effects, pregnancy, infection risk, stomach problems, and interactions, so the dose and safety decision belong to a qualified prescriber.

An antiviral medicine may be added in selected cases, especially when weakness is severe, but antivirals alone have not shown the same benefit as timely corticosteroids for typical Bell palsy. A blistering ear rash or other evidence of shingles changes the clinical question and may affect treatment. Do not use leftover steroids or antiviral medicine, and do not delay evaluation while trying supplements or facial devices.

Pain may be managed with an appropriate over-the-counter option if it is safe with the person’s other conditions and medicines. The pharmacist or clinician can advise. Severe, escalating, or unusual pain should prompt reassessment rather than repeated self-medication.

Protecting the eye

An eyelid that does not close fully leaves the cornea exposed to drying, scratches, and infection. This can threaten vision. The care plan may include preservative-free lubricating drops while awake, lubricating ointment at night, glasses or a moisture chamber, and careful eyelid closure or taping for sleep. Technique matters because tape placed on the eye surface can injure it. Ask a clinician or eye professional to demonstrate.

Check the eye for redness, pain, a gritty sensation, light sensitivity, discharge, or blurred vision. Seek urgent eye care if any of these develop, if the eye was exposed to dust or chemicals, or if the person cannot reliably protect it. Contact lens use may need to pause until closure and tear protection are adequate.

Do not patch the eye continuously without clinical advice. A patch can hide worsening irritation, and a poorly fitted patch may press on the cornea. Eye protection should preserve moisture while allowing regular inspection.

Recovery, rehabilitation, and follow-up

Arrange follow-up if weakness is not beginning to improve within the expected period, if symptoms worsen after the first few days, or if recovery remains incomplete after about three months. The clinician may reconsider the diagnosis or refer to neurology, ear-nose-throat care, ophthalmology, or a facial nerve specialist.

People with residual weakness or synkinesis may benefit from specialized facial neuromuscular retraining. This uses gentle, precise movement and relaxation work rather than forceful repetitive exercise. Aggressive facial exercise, electrical stimulation, or unregulated devices can reinforce unwanted movement patterns and should not be started without expert guidance.

Botulinum toxin or selected surgical procedures may help particular long-term problems, but each has tradeoffs and requires an experienced specialist. Cosmetic appearance, eating, speech, eye comfort, and emotional wellbeing are all valid treatment goals. Anxiety, embarrassment, and social withdrawal are common and deserve support.

Pregnancy, children, and recurrent symptoms

Pregnant or recently postpartum patients with new facial weakness need urgent assessment for the same neurologic emergencies as anyone else. Blood pressure and pregnancy-related complications may also need review. A clinician can weigh the timing and safety of treatment rather than assuming pregnancy prevents therapy.

Facial palsy in a child deserves pediatric evaluation because the range of causes differs and Bell palsy is less common than in adults. Tick exposure, ear infection, trauma, congenital conditions, and other neurologic findings may change testing and care.

A second episode should not be managed only by repeating an old prescription. Document which side is affected, time of onset, associated symptoms, previous recovery, and any family history, then seek a new examination.

Preparing for care

Write down the exact onset time and whether weakness was sudden or progressive. Bring a medicine and supplement list and note recent infection, rash, ear symptoms, tick exposure, travel, vaccination, pregnancy, diabetes, injury, or previous facial weakness. If safe, take a short video showing eyebrow raise, gentle eye closure, smile, and speech to show change over time.

Ask which findings support Bell palsy, how stroke and other causes were considered, whether any tests are needed, and how to protect the eye. Clarify the treatment window, expected recovery, medicine risks, follow-up date, and symptoms that require emergency or eye care.