Bell’s Palsy (Facial Paralysis): Detailed Guide

Author: Op. Dr. Javidan Asafov · ENT / Otolaryngology Specialist · Last medical review: 27.09.2026

Definition and frequency

Bell’s palsy is a sudden, one-sided, peripheral paralysis of the facial nerve for which no other cause can be found. It affects roughly 15 to 30 people per 100,000 each year; it can occur at any age but is most common between 15 and 45, and men and women are affected equally. Symptoms begin within hours and reach their worst within 72 hours at most. Facial weakness that progresses slowly over more than three days, or develops over weeks, does not fit the definition of Bell’s palsy and is investigated for other causes.

After leaving the brainstem, the facial nerve runs through a long, narrow bony canal inside the skull, passes right beside the middle ear and branches within the salivary gland in front of the ear (the parotid) to reach the facial muscles. Along the way it controls not only the muscles of facial expression but also tear and saliva production, taste on the front two-thirds of the tongue and a small muscle in the middle ear. This is why the palsy can cause a dry eye, altered taste and sounds seeming too loud. Compression of the swollen nerve inside the canal is regarded as the core mechanism; the strongest evidence points to reactivation of herpes simplex virus lying dormant in the nerve.

Telling peripheral from central palsy

Because the forehead muscles receive signals from both halves of the brain, damage originating in the brain (central) spares forehead movement and weakens only the lower half of the face. When the facial nerve itself is affected, the forehead, eye and mouth are involved together. The distinction is made by asking the patient to raise the eyebrows, close the eyes tightly, show the teeth and whistle. If the forehead is spared, or if there are additional neurological signs such as arm or leg weakness, slurred speech, double vision, difficulty swallowing or unsteadiness, a stroke assessment comes first.

Causes other than Bell’s palsy

Ramsay Hunt syndrome: Reactivation of the chickenpox–shingles virus in the facial nerve. Fluid-filled blisters on the ear, in the ear canal or on the palate, severe ear pain and sometimes hearing loss or dizziness accompany it. The blisters may appear after the paralysis. It runs a more severe course than Bell’s palsy with a lower rate of complete recovery, and an antiviral is always added to the steroid.

Ear diseases: Acute middle-ear infection, chronic middle-ear infection with cholesteatoma and a spreading infection of the ear canal (malignant otitis externa) can affect the facial nerve directly. This is why the eardrum and ear canal are examined in every case of facial palsy; in patients with ear discharge, hearing loss or a history of chronic ear disease, treatment is directed at the underlying disease and often requires surgery.

Other causes: Skull-base fractures, tumours of the salivary gland or nerve sheath, Lyme disease, sarcoidosis and diabetic nerve damage. Involvement of both sides, recurrence, slow progression, no improvement at all after three months, or a lump in front of the ear all call the diagnosis of Bell’s palsy into question and require imaging.

Diagnosis

Examination: The diagnosis is made from the history and examination. The degree of paralysis is graded from 1 (normal) to 6 (complete paralysis) on the House–Brackmann scale according to forehead, eye and mouth movement; this grade guides treatment and is used to track recovery. How far the eye can close is noted separately.

Ear and neck examination: The eardrum, ear canal and outer ear are checked for blisters, infection or cholesteatoma, and the parotid region and neck are examined for lumps. Patients with ear symptoms have a hearing test.

Imaging and blood tests: In typical Bell’s palsy, MRI, CT or routine blood tests are not needed at first and guidelines do not recommend them. Imaging is planned when there are additional neurological signs, recurrent or bilateral palsy, slow progression, suspected ear disease, or no improvement after three months. A Lyme test is requested if there has been a tick bite or travel to an endemic area.

Electrophysiological tests: In complete paralysis, electroneurography (ENoG) performed between days 3 and 14 measures the proportion of nerve damage. A loss of more than 90% compared with the healthy side predicts slow and possibly incomplete recovery, and these patients are followed more closely. These tests are not needed in partial paralysis.

Treatment options

Corticosteroids

International guidelines strongly recommend starting oral corticosteroids within 72 hours of symptom onset in patients over 16. The course lasts about ten days; the medicine is not stopped abruptly but tapered off gradually. In a study of around 500 patients, the complete recovery rate at nine months reached 94% in those given early prednisolone, compared with 82% in those who were not. Because the benefit is not entirely lost after 72 hours, steroids are usually still started in patients who present within the first week. Blood sugar is monitored closely in people with diabetes; in uncontrolled high blood pressure, glaucoma, an active stomach ulcer and some psychiatric conditions the balance of risk and benefit is weighed individually.

Antiviral medicines

Antivirals on their own have not been shown to help and guidelines do not recommend them. Added to steroids, however, they have been reported to give a small extra gain in the chance of complete recovery, especially in severe and complete palsy; adding an antiviral for about a week is therefore offered as an option in severe cases. In Ramsay Hunt syndrome antiviral treatment is not an option but a necessity.

Eye protection

When the eyelid cannot close, the cornea dries out and an ulcer with permanent loss of vision can develop on the exposed surface; this is the most important preventable complication of Bell’s palsy. Preservative-free artificial tears every 1–2 hours during the day, an eye ointment at bedtime and keeping the eye closed with tape or a moisture chamber are recommended. Glasses protect the eye from wind and dust outdoors. Redness, pain, sensitivity to light or blurred vision in the eye needs an eye specialist’s assessment the same day.

Facial exercises and physiotherapy

Controlled facial exercises done in front of a mirror several times a day and gentle massage of the facial muscles help regain muscle control during recovery; in patients whose recovery is prolonged, specialised facial nerve physiotherapy (neuromuscular retraining) is effective in reducing synkinesis. Guidelines state that there is insufficient evidence for electrical stimulation and acupuncture; these methods should not replace effective treatment.

Surgery

Surgical decompression of the facial nerve inside its bony canal is an option discussed at experienced centres only for very carefully selected patients with complete paralysis, more than 90% damage on ENoG and assessment within the first two weeks; guidelines make no routine recommendation. In patients left with permanent paralysis, procedures that restore facial symmetry and eye closure, such as placing a gold weight in the upper eyelid and brow or mouth-corner suspension, come into consideration.

Special situations

Pregnancy: Bell’s palsy is about three times more common during pregnancy, especially in the last three months and the first week after delivery, than in women who are not pregnant. Steroid treatment can usually be given after a joint decision with the obstetrician; recovery rates in pregnancy have been reported to be slightly lower.

Children: Bell’s palsy is less common in children and mostly resolves completely even without treatment; the added benefit of steroids has not been shown as clearly in children as in adults. Because causes such as middle-ear infection and Lyme disease are more frequent in this age group, the ear examination and history matter even more; the decision is made together with the paediatrician.

Diabetes and high blood pressure: Both raise the risk of the condition and call for close monitoring during steroid treatment; treatment is not withheld, monitoring is stepped up.

Recovery and lasting effects

In about 85% of patients signs of improvement begin within the first three weeks; in the rest, improvement may appear between three and six months. Almost all patients who start with partial paralysis and about two-thirds of those who start with complete paralysis recover fully. Complete paralysis at onset, age over 60, diabetes, marked pain and no improvement at all in the first three weeks are warning signs of incomplete recovery.

As nerve fibres regrow they can reach the wrong targets; this can lead to involuntary linked movements such as the eye narrowing when smiling or the corner of the mouth moving when blinking (synkinesis), watering of the eye while eating (“crocodile tears”) and a feeling of tightness in the face. These signs usually become noticeable after the third to sixth month of recovery. Targeted physiotherapy and small doses of botulinum toxin in the overactive muscles reduce these complaints markedly. Facial palsy recurs on the same or the opposite side in about 7–10% of patients; in recurrent cases the underlying cause is investigated again.

Follow-up

The first check-up after starting treatment is usually within two weeks; eye protection is reviewed and the degree of paralysis is graded again. If there is still no improvement after three months, or a new neurological sign appears, imaging is planned and the case is reviewed jointly with a centre experienced in facial nerve disorders. Patients who recover fully need no further check-ups.

Frequently asked questions

Can cold weather, air conditioning or a draught cause facial palsy? No link has been proven. The slight rise in cases in winter is attributed to the viral infections common at that time rather than to the cold itself. Protecting yourself from the cold does no harm, but waiting with the thought “I caught a chill, it will pass” leads to missing the treatment window.

How long does it take to go away? In most patients the first signs begin to improve within 2–3 weeks; full recovery usually takes 2–3 months and may extend to 6–9 months in some. Early improvement is a good sign.

Is it contagious? No. The mechanism is reactivation of a virus in the person’s own nerve; the patient does not pass paralysis on to others.

Should I use heat or massage? A warm compress can ease pain behind the ear; gentle facial massage and mirror exercises are useful during recovery. Vigorous massage, “exercising the muscles” with hard-to-chew gum, or electrical stimulation of the face are not recommended.

I am worried about steroid side effects. Can I do without them? A short ten-day course is different from the known side effects of long-term steroid use; temporary sleeplessness, increased appetite and a rise in blood sugar may occur. On the other hand, steroids are the only proven treatment that clearly reduces the chance of permanent facial asymmetry. In special situations such as diabetes, the decision is made together with your doctor.

Can dental treatment or flying trigger the palsy? There is no reliable evidence that tooth extraction or flying causes Bell’s palsy, and there is no objection to flying while you have the palsy.

This article is for general information; please consult your physician for diagnosis and treatment.