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Taking a corticosteroid within 72 hours of Bell’s palsy first appearing reduces the number of people with incomplete facial recovery after six months.

Bell’s palsy is a sudden onset of weakness or paralysis of the muscles on one side of the face. Most people recover completely within nine months, often with no treatment, but about three in 10 people are left with some weakness or unwanted facial movements.

This Cochrane review found that ten people needed to be treated with corticosteroid, compared to placebo tablets, to avoid one incomplete recovery. It also showed that side effects were uncommon and mild.

Corticosteroids are often already prescribed to treat Bell’s palsy in practice. This review confirms that they help. Any further trials should compare different corticosteroids against each other, rather than placebo, to find the best options in terms of timing, drug and dose.

Why was this study needed?

Bell’s palsy affects about 12,000 people in the UK each year. It is most common in people aged 15 to 60 years.

Bell’s palsy is caused by inflammation or compression of the facial nerve, which controls the facial muscles. The cause is unknown, but it has been associated with viral infections such as the herpes virus. Occasionally the nerve can regrow along incorrect channels and lead to “synkinesis”, abnormal facial movements, or other major problems such as watering of the eye when eating. These can be particularly bothersome, long term problems for which rehabilitation is needed. This review included these problems as outcomes, but excluded some trials of antiviral treatments that were in previous reviews.

Corticosteroids have been used for some time to treat Bell’s palsy. They help to reduce inflammation and swelling, which may limit any nerve damage. This is an update of a previous Cochrane review to determine whether the strength of evidence is sufficient that their effectiveness can be considered certain.

What did this study do?

This systematic review pooled the results of seven randomised controlled trials, with a total of 895 participants, which compared corticosteroids with placebo or with no treatment. People in the studies were aged from two to 84 years, with one-sided Bell’s palsy. Six of the trials used prednisone or prednisolone, with a variety of doses and one used cortisone acetate.  In five of the trials, treatment was started within three days of the onset of symptoms. The main outcome of interest was incomplete recovery of facial movement after six months or more.

The included studies were rated as moderate to high quality for the main outcomes, which means that the results are reliable.

What did it find?

  • Corticosteroids were more effective than placebo or no treatment for reducing incomplete recovery of facial movement after six months or more. Overall, 79/452 (17%) of participants taking corticosteroids had incomplete facial recovery after six months, compared with 125/447 (28%) in the control group (risk ratio (RR) 0.63, 95% confidence interval [CI] 0.50 to 0.80).
  • Ten people needed to be treated with corticosteroids to stop one person being left with facial weakness (95% CI 6 to 20).
  • There was a significant reduction in abnormal facial movements during follow-up in participants receiving corticosteroids (RR 0.64, 95% CI 0.45 to 0.91) three studies.
  • Three studies specifically noted that there were no side effects that were caused by the corticosteroids. Combined data from three studies that recorded non-serious side effects showed no difference in rates between people taking corticosteroids and those taking placebo (RR 1.04, 95% CI 0.71 to 1.51).

What does current guidance say on this issue?

There is no national clinical guideline on the management of Bell’s palsy. Clinical Knowledge Summaries (NICE summaries of evidence for primary care) recommend that healthcare professionals should consider prescribing prednisolone for people if they are seen within 72 hours of symptoms starting.

There is no agreement on the best dose and regimen, but two options are given.

What are the implications?

This review confirms that there is enough evidence from randomised controlled trials against placebo to support the use of corticosteroids to treat Bell’s palsy within 72 hours of onset. There remains uncertainty over the best drug, dose or how long it should be taken. Future trials should compare different corticosteroids or dosing regimens.

Long term complications, such as unwanted facial movements, can still be troublesome. Treatment that reduces these might also improve recovery from this common condition.


Citation and Funding

Madhok VB, Gagyor I, Daly F, et al. Corticosteroids for Bell's palsy (idiopathic facial paralysis). Cochrane Database Syst Rev. 2016;7:CD001942

Cochrane UK and the Neuromuscular Cochrane Review Group are supported by NIHR infrastructure funding.



Clinical Knowledge Summaries. Bell’s palsy. London: National Institute for Health and Care Excellence; 2012.

NHS Choices. Bell’s palsy. London. Department of Health; 2014.

Produced by the University of Southampton and Bazian on behalf of NIHR through the NIHR Dissemination Centre

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Long term problems are particularly troublesome for two out of ten people following Bell’s palsy. NHS choices describe some of these:

  • Eye-mouth synkinesias – a result of the nerve growing back in a different way. It can cause the eye to wink when eating, laughing or smiling. Sometimes it can become so severe that the eye can close completely during meals.
  • Facial tightness (contracture) – facial muscles are permanently tense. It can lead to facial disfigurement such as the eye becoming smaller, the cheek becoming more bulky, or the line between the nose and the mouth becoming deeper.
  • Loss or reduced sense of taste – when damaged nerves do not repair properly.
  • Tears when eating, known as ‘crocodile tears’.
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