Insufficient evidence for effectiveness of any treatment for oral lichen planus

The Cochrane Oral Health Group Trials Register, Cochrane Central Register of Controlled Trials (CENTRAL), Medline and Embase databases were searched with no restrictions regarding language or date of publication. Bibliographies of identified publications were also checked for relevant studies, and authors were contacted to identify missing and unreported trials. The WHO International Trials Registry Platform was searched for ongoing studies, using the term 'oral lichen planus'.

Randomised controlled clinical trials (RCTs) of therapy for symptomatic OLP which compared treatment with a placebo or between treatments or no intervention were considered for this review.

The titles and abstracts of all reports identified were scanned independently by two review authors. All studies meeting the inclusion criteria were assessed for risk of bias and data were extracted. For dichotomous outcomes, the estimates of effects for the intervention were expressed as risk ratios (RR) together with 95% confidence intervals. For continuous outcomes, mean differences (MD) and 95% confidence intervals were used to summarise the data. Meta-analyses were conducted for studies with similar comparisons reporting the same outcome measures.

Twenty-eight trials were included. Although topical steroids are considered first line treatment for symptomatic OLP, we identified no RCTs that compared steroids with placebo. There is no evidence from the three trials of pimecrolimus that this treatment is better than placebo in reducing pain from OLP. There is weak evidence from two trials, at unclear and high risk of bias respectively, that aloe vera may be associated with a reduction in pain compared to placebo, but it was not possible to pool the pain data from these trials. There is weak and unreliable evidence from two small trials, at high risk of bias, that cyclosporin may reduce pain and clinical signs of OLP, but meta-analysis of these trials was not possible.There were five trials that compared steroids with calcineurin inhibitors, each evaluating a different pair of interventions. There is no evidence from these trials that there is a difference between treatment with steroids compared to calcineurin inhibitors with regard to reducing pain associated with OLP. From six trials there is no evidence that any specific steroid therapy is more or less effective at reducing pain compared to another type or dose of steroid.

From the 28 trials included in this systematic review, the wide range of interventions compared means there is insufficient evidence to support the effectiveness of any specific treatment as being superior.