Bell’s palsy is a neurological condition that affects the facial nerve causing weakness down one side of the face. Many cases of Bell’s palsy arise after a viral infection, which leads to swelling of the facial nerve.

The symptoms of Bell’s palsy usually disappear with time without any long-term effects.

Bell’s palsy and the facial nerve

Bell’s palsy is due to minor damage of the facial nerve. This nerve controls the movement of muscles and also passes information from the face to the brain and back again. It is the nerve that allows us to have different facial expressions, to cry, to speak and to produce saliva.

Viral infections are one established cause of inflammation in the facial nerve that then results in Bell’s palsy. Infection with Herpes simplex virus (the cold sore virus), varicella-zoster virus (the virus that causes chicken pox and shingles), influenza and viral hepatitis have all been associated with Bell’s palsy. 

Sometimes, however, the exact cause is difficult to pin down. Genetic factors are thought to play a role, as development of Bell’s palsy is more common if you have a family member who has had the condition. It has also been associated with:

  • Fractures of the face
  • Multiple sclerosis
  • Diabetes
  • Some types of cancer.

Symptoms of Bell’s palsy

The most common symptom of Bell’s palsy is weakness of one side of the face. This makes it difficult to close your eye on that side and affects smiling, raising the eyebrows and whistling as your muscles can’t form the right mouth shape.

Other common symptoms of Bell’s palsy include:

  • A dull pain or ache just behind the ear.
  • Either producing too many tears or too few leading to watery eyes or dry eyes.
  • Losing the sensation of taste in the front part of the tongue.
  • Sounds seeming louder in one ear than in the other.

Understandably, because of these symptoms, people with Bell’s palsy often worry they might have had a minor stroke. It is more usual for a stroke to affect one whole side of the body and not just the face but you will probably need to arrange to see your GP to reassure you.

If you have symptoms that are similar to those of Bell’s palsy but spread from your face and move down your body, you need to get emergency medical attention as this could be due to a stroke.

The symptoms of Bell’s palsy usually take a few hours to a few days to fully develop and resolve within 2–3 weeks in most people.

How common is Bell’s palsy?

Bell’s palsy is quite common, affecting 1 in 60 people. Pregnant women are particularly prone to it and you are also more likely to develop it if you have diabetes, you have had flu or another respiratory infection, you have had a viral infection, particularly chicken pox or shingles, or if Bell’s palsy runs in the family.

Men and women are equally affected by Bell’s palsy and it has 2 age peaks – young people and adults (aged 10 to 30), and then older people (over 70). If you have had Bell’s palsy once, you can get it again. Recurrence occurs in around 7 out of every 100 people and usually happens at approximately 10 year intervals.

Diagnosing Bell’s palsy

There is no test that can specifically diagnose Bell’s palsy. Instead, your GP will take your medical history into account and go on the symptoms that you have. If he or she is not sure whether you have Bell’s palsy or some other neurological condition, you may have to have a CT scan or an MRI scan to confirm what the problem is.

Do I need treatment?

Most people find that the symptoms of Bell’s palsy fade naturally after a few weeks. You don’t have to have treatment but it can speed-up recovery and it can reduce the risk of long-term nerve damage. Medicines that you might be prescribed include:

  • Corticosteroid tablets, such as prednisolone. These reduce the swelling around the facial nerve.
  • Anti-viral tablets, such as aciclovir (acyclovir) or valaciclovir (valacyclovir), which limit the damage done by a viral infection.

Coping with Bell’s palsy

Until they resolve, the symptoms can be troublesome and cause some distress. Because Bell’s palsy often causes the eye on the affected side to stay open, you might find artificial tears or other lubricating agents useful to prevent your eye drying out. Some people find that physiotherapy to help strengthen the facial muscles on the affected side can help them to return to normal more quickly.

For 75% of people, symptoms disappear altogether. The rest experience some continued muscle weakness and facial weakness and notice that their episode of Bell’s palsy has changed the appearance of their face. This is because the damage to the facial nerve causes shortening of the facial muscles, causing different parts of the face to move together. You might find, for example, that your chin moves when you blink.

You may be at a higher risk of developing long-term problems if:

  • You were completely unable to move your face when the Bell’s palsy was at its worst.
  • You are over 60.
  • You have high blood pressure (hypertension) or diabetes.
  • You are pregnant.
  • You have had a long period of symptoms which show no signs of abating after 6 weeks.

If this happens, you may need to be referred to a neurologist to find out if anything can be done to help.