Facial palsy

What is facial palsy?

Facial palsy is weakness or paralysis of the muscles on one or both sides of the face, caused by damage to the facial nerve that controls them. Bell's palsy, which is usually temporary and affects one side of the face, is by far the most common cause, accounting for around 80% of cases.

Symptoms of facial palsy

Symptoms depend on the underlying cause and how severe the nerve damage is, but with Bell's palsy, symptoms typically come on suddenly, over a few hours to a few days, and usually affect one side of the face. These can include:

• weakness, or a complete inability to move one side of your face, causing it to droop
• difficulty closing your eye on the affected side, which can lead to dryness and irritation, or, if the eye overcompensates, watering
• drooling, or difficulty eating and drinking, as food can become trapped on the weaker side
• a dry mouth, and a loss or change in your sense of taste
• pain, which may be sharp and felt in or around your ear, sometimes starting before the weakness appears
• difficulty speaking clearly, particularly with certain sounds
• sensitivity to loud noises, or ringing in your ear (tinnitus).

Rarely, facial palsy affects both sides of the face at once.

Causes and who is at risk

Although Bell's palsy is the best-known cause, there are more than 50 recognised causes of facial palsy, and treatment and outlook depend heavily on which one applies to you. Causes include:

• Bell's palsy, which is an idiopathic condition, meaning no single cause has been identified, though links have been made to viral infections, a weakened immune system and stress
• viral infections, such as Ramsay Hunt syndrome or, in some cases, herpes simplex, chickenpox or shingles, Epstein-Barr virus, or COVID-19
• bacterial infections, such as Lyme disease, or a middle ear infection
• surgical causes, for example during removal of a tumour on or near the facial nerve, or surgery on the parotid (salivary) gland
• traumatic injury, including fractures to the skull or face, or, in babies, trauma during a difficult birth
• neurological conditions, such as Guillain-Barré syndrome or neurofibromatosis type 2
• congenital causes, where the facial nerve or muscles don't develop typically in the womb, sometimes linked to rare genetic syndromes
• stroke, which can also cause facial weakness, but works differently as it damages the brain itself rather than the facial nerve directly.

For Bell's palsy specifically, you may be at higher risk if you have diabetes, high blood pressure, obesity, or are pregnant, particularly in the third trimester, and it's somewhat more common in winter.

Are there different types of facial palsy?

Facial palsy can be classified in a few ways.

By degree of nerve injury

• First degree: The nerve is only bruised or concussed, and usually recovers within 8 weeks
• Second degree: More significant damage, though the nerve's outer layer stays intact – the first signs of recovery tend to appear at around 4 months as the nerve slowly repairs itself
• Third degree: This is the most severe damage – recovery is much slower and often incomplete, and if the nerve has been completely severed, surgery may be needed to restore facial function.

By timing

• Congenital facial palsy: Present from birth, either because the facial nerve or muscles didn't develop typically in the womb, or due to trauma during a difficult delivery
• Acquired facial palsy: Develops later in life, from any of the causes listed above.

How is facial palsy diagnosed?

Diagnosis usually starts with a doctor examining your face and asking you to make specific movements, such as closing your eyes, raising your eyebrows, puckering your lips or smiling.

For Bell's palsy specifically, a key finding is weakness affecting your whole forehead on the affected side. A stroke, in contrast, usually spares the forehead.

Bell's palsy is generally a 'diagnosis of exclusion', meaning your doctor confirms it partly by ruling out other possible causes. Depending on your symptoms, you may also have the following:

• Blood tests: These are to check for conditions such as Lyme disease or sarcoidosis
• Imaging: Such as an MRI or CT scan, to rule out a stroke, tumour or multiple sclerosis
• Electromyography (EMG): This is a nerve test that can show how much the facial nerve has been affected and help predict how quickly you're likely to recover
• A lumbar puncture: This is used in some cases to check for infections such as meningitis or Lyme disease.

How is facial palsy treated?

Non-surgical treatment

For Bell's palsy, the main initial treatment is a short course of oral steroids, usually prednisolone for around 10 days, which helps reduce nerve swelling and improve your chances of a full recovery. This works best when started within the first couple of days of your symptoms appearing. After around 72 hours, there's no good evidence that steroids improve recovery.

If Ramsay Hunt syndrome is suspected, for example because of a rash or blisters around your ear, an antiviral medicine is usually added, though antivirals alone don't appear to improve outcomes in straightforward Bell's palsy.

Protecting your eye is a priority if you can't fully close it. This usually involves:

• artificial tears or lubricating eye drops during the day, to stop your eye drying out
• a thicker ointment at night
• taping your eye closed at bedtime, or wearing an eye patch, if you can't close it at all.

It's tempting to try forceful facial exercises to speed things up, but this isn't recommended, as it may encourage abnormal nerve regrowth, called synkinesis, or make the unaffected side over-compensate. Gentle facial massage is a safer alternative.

If your symptoms haven't fully improved within around 3 months, ask your GP to refer you to a physiotherapist or speech and language therapist experienced in facial palsy, for facial rehabilitation therapy. A specialist may also offer injections to relax overactive or twitchy muscles and even out your facial expression.

Surgical treatment

Surgery isn't usually needed for Bell's palsy, since around 8 in 10 people recover well without it. It's generally only considered in a small number of cases where severe symptoms persist for at least 2 years, and only after a course of facial rehabilitation therapy has been tried first.

For facial palsy caused by other conditions, for example if the facial nerve has been completely severed by an injury or during tumour surgery, surgical repair of the nerve may be needed to restore function. Functional facial plastic surgery can also help with longer-term problems, such as correcting facial asymmetry or helping an eyelid close properly.

When should I see a doctor?

Call 999 immediately if the face droops on one side, someone can't lift both arms and keep them there, or they have sudden difficulty speaking, such as slurred or garbled speech, as these can be signs of a stroke, which is a medical emergency. A health professional should always assess this urgently rather than you trying to tell the difference yourself.

Ask for an urgent GP appointment, or call 111, if you have symptoms of facial weakness, ideally within 72 hours, since treatment for Bell's palsy works best when started early.

Once you have a diagnosis, contact your doctor if:

• your symptoms haven't started improving within 3 months
• you have ongoing eye irritation or your eyelid won't close
• you're finding it hard to drink or swallow enough
• you develop hearing loss, dizziness or vertigo.