Bell's palsy Bell's palsy is the most common cause of facial palsy, when the facial nerve becomes damaged or inflamed. This nerve controls muscles in the face and carries taste sensations from the front of the tongue.

In this article

What causes it? What are the symptoms?

Who's affected? Can it be prevented?

What's the treatment?

The precise cause of Bell's palsy remains unknown. Viral infection is believed to play a part, causing inflammation that presses on the nerve. Lyme disease and herpes simplex virus are believed to be common triggers of Bell’s palsy.

Damage or inflammation of the facial nerve results in weakness or paralysis of one side of the face. Partial or complete paralysis may result in drooping of the eyelid and the corner of the mouth on the affected side.

Other symptoms may include hypersensitivity to sound in the affected ear, watering of the eye, drooling from the mouth on the affected side and impairment of taste. It may also be difficult to close the eye on the affected side.

Facial palsy also occurs in Ramsay Hunt syndrome, caused by the spread of the herpes varicella-zoster (shingles) virus to the facial nerve.

Other symptoms of Ramsay Hunt syndrome include intense ear pain, a rash around the ear, loss of hearing, vertigo, tinnitus, loss of taste, a dry mouth and dry eyes.

Bell's palsy affects around one in 4,000 people in the UK each year, and around one in 70 people in a lifetime. It can occur in people of all ages, but most commonly between the ages of 15 and 45. Those with weakened immune systems are more likely to develop the condition, as are pregnant women and those with diabetes.

It can occur in people of all ages, but those with weakened immune systems are more likely to develop the condition.

Since the precise cause of Bell's palsy is unknown and it tends to appear suddenly over 24 hours, it's difficult to prevent. Maintaining a strong immune system may help reduce your risk.

For most people, Bell’s palsy gets better without the need for treatment.

Steroids to reduce inflammation may help, as may antiviral therapy. Painkillers may also be required.

It's important to protect the eye from drying, which may result in infection and ulceration. Artificial tears are often recommended to keep the eyes moist.

Up to around 80 per cent of people make a full recovery within three months.

This article was last medically reviewed by Dr Rob Hicks in November 2007