We reviewed the evidence about the effect of antiviral therapy alone or in combination with any other therapy, on Bell's palsy.
Bell's palsy is a disease of the facial nerve that causes one side of the face to be paralysed. Some studies have suggested that it is caused by the same viral infections that cause cold sores (herpes simplex) or shingles (varicella zoster). If this is correct, antiviral drugs would be likely to help recovery. The paralysis is usually temporary even when left untreated, although without treatment about one person in five is left with permanent facial disfigurement or pain. A Cochrane review has already confirmed the effectiveness of corticosteroids in Bell’s palsy. This review was first published in 2001 and has been revised several times, most recently in 2009. This version replaces an update in Issue 7 of the Cochrane Library withdrawn because of an ongoing investigation into the reliability of data in one of the included studies.
We identified 10 trials, which included 2280 participants with mild, moderate, or severe one-sided Bell’s palsy of unknown cause. Participants were aged from 14 to 84 years. The trials compared antivirals in combination with corticosteroids to corticosteroids; antivirals alone to placebo or no treatment; antivirals alone to corticosteroid treatment alone; and antiviral treatment in combination with corticosteroids to placebo or no treatment. The duration of the included studies ranged from three months to 12 months.
Key results and quality of the evidence
According to low-quality evidence, combining antivirals with corticosteroids improved rates of incomplete recovery from Bell's palsy compared to corticosteroids alone. This finding was based on data from eight trials involving 1315 people with Bell's palsy of various degrees of severity.
We were able to use data from four of the studies (478 participants) to examine treatment effects in severe Bell's palsy (that is people who have complete or almost-complete facial paralysis). The results showed that in this group, the addition of antiviral treatment to corticosteroids probably improved rates of incomplete recovery over corticosteroid treatment alone, although we assessed this evidence as low quality.
In other analyses, we found the following:
• corticosteroids alone were more effective than antivirals alone in terms of incomplete recovery (768 participants);
• antivirals plus corticosteroids were more effective than placebo or no treatment (658 participants); and
• antivirals alone were less effective than placebo (although this difference was not significant) (658 participants).
Long-term after-effects of Bell's palsy
Three trials (941 participants) assessed the long-term after-effects of Bell's palsy, such as excessive tear production and synkinesis (involuntary movement of muscles occurring at the same time as deliberate movement). The combination of antivirals and corticosteroids reduced long-term after-effects of Bell's palsy compared with corticosteroids alone. The evidence was of moderate quality.
There were fewer long-term after-effects of Bell's palsy after treatment with corticosteroids alone than with antivirals alone (two trials, 472 participants).
Based on the evidence from three trials (1528 participants), none of the treatments showed significant differences in adverse events, taking into account that the evidence for this outcome was low quality.
The evidence in this review is current to October 2014.
Low-quality evidence from randomised controlled trials showed a benefit from the combination of antivirals with corticosteroids compared to corticosteroids alone for the treatment of Bell's palsy of various degrees of severity. Low-quality evidence showed a benefit of combination therapy compared with corticosteroids alone in severe Bell’s palsy. Corticosteroids alone were more effective than antivirals alone and antivirals plus corticosteroids were more effective than placebo or no treatment. There was no benefit from antivirals alone over placebo.
Moderate-quality evidence indicated that the combination of antivirals and corticosteroids reduced sequelae of Bell's palsy compared with corticosteroids alone.
We found no significant increase in adverse events from the use of antivirals compared with either placebo or corticosteroids, based on low-quality evidence.
Corticosteroids are widely used in the treatment of idiopathic facial paralysis (Bell’s palsy), but the effectiveness of additional treatment with an antiviral agent is uncertain. Significant morbidity can be associated with severe cases of Bell's palsy. This review was first published in 2001 and revised several times, most recently in 2009. This version replaces an update of the review in Issue 7 of the Cochrane Library subsequently withdrawn because of an ongoing investigation into the reliability of data from an included study.
To assess the effects of antiviral treatments alone or in combination with any other therapy for Bell’s palsy.
On 7 October 2014 we searched the Cochrane Neuromuscular Disease Group Specialized Register, CENTRAL, MEDLINE, EMBASE, LILACS, DARE, NHS EED, and HTA. We also reviewed the bibliographies of the identified trials and contacted trial authors and known experts in the field and relevant drug companies to identify additional published or unpublished data. We searched clinical trials registries for ongoing studies.
We considered randomised controlled trials or quasi-randomised controlled trials of antivirals with and without corticosteroids versus control therapies for the treatment of Bell's palsy. We excluded trials that had a high risk of bias in several domains.
Pairs of authors independently assessed trials for relevance, eligibility, and risk of bias, using standard Cochrane procedures.
Ten trials, including 2280 participants, met the inclusion criteria and are included in the final analysis. Some of the trials were small, and a number were at high or unclear risk of bias. Other trials did not meet current best standards in allocation concealment and blinding.
We found a significant benefit from adding antivirals to corticosteroids in comparison with corticosteroids alone for people with Bell’s palsy (risk ratio (RR) 0.61, 95% confidence interval (CI) 0.39 to 0.97, n = 1315). For people with severe Bell’s palsy (House-Brackmann scores of 5 and 6 or the equivalent in other scales), we found a reduction in the rate of incomplete recovery at month six when antivirals plus corticosteroids were used, compared to corticosteroids alone (RR 0.64, 95% CI 0.41 to 0.99, n = 478). The outcome for the participants receiving corticosteroids alone was significantly better than for those receiving antivirals alone (RR 2.82, 95% CI 1.09 to 7.32, n = 768). The treatment effect of placebo was significantly lower than that of antivirals plus corticosteroids (RR 0.56, 95% CI 0.41 to 0.76, n = 658). Antivirals alone produced no benefit compared with placebo (RR 1.10, 95% CI 0.87 to 1.40, n = 658).
Motor synkinesis or crocodile tears
In two trials comparing antivirals and corticosteroids with corticosteroids and placebo that assessed this outcome, we found a significant difference in long-term sequelae in favour of antivirals plus corticosteroids (RR 0.56, 95% CI 0.36 to 0.87, n = 469). Two trials comparing antivirals alone with corticosteroids alone investigating this outcome showed fewer sequelae with corticosteroids (RR 1.52, 95% CI 1.08 to 2.12, n = 472). We found no data on long-term sequelae for other comparisons.
Adverse event data were available in three studies giving comparison data on 1528 participants. None of the four comparisons (antivirals plus corticosteroids versus corticosteroids plus placebo or no treatment; antivirals versus corticosteroids; antivirals plus corticosteroids versus placebo; antivirals versus placebo) showed significant differences in adverse events between treatment and control arms. We could find no correlation with specific treatment within these results.