The aim of this Cochrane review was to assess the effectiveness and safety of interventions to treat symptomatic, biopsy-proven oral lichen planus (OLP). OLP is a common chronic autoimmune disease associated with cell-mediated immunological dysfunction. The prevalence has been reported as 1.27% and it is more frequently seen in women aged between 30 and 60 years. There are a variety of clinical presentations reticular, papular, plaque, atrophic and ulcerative (erosive), with reticular being the most common.

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.  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. 28 trials were included the review  with pain being the primary outcomes as it is the indication for treatment of OLP.

They found that:

• Although topical steroids are considered the first line treatment, no RCTs  were identified 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.

They concluded:

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

And highlighted the following implications for research:

There is a stringent need to standardise the methodology of OLP intervention trials mainly in relation to the assessment used. Future trials should measure the outcomes of symptoms and clinical assessment using standardised measures. It has been difficult to compare the effectiveness of drugs within and between individual patients, and different institutions. Moreover, long-term follow-up, adverse effects of treatment and cost-effectiveness should be included in the trials.

Thongprasom K, Carrozzo M, Furness S, Lodi G. Interventions for treating oral lichen planus. Cochrane Database Syst Rev. 2011 Jul 6;7:CD001168. PubMed PMID:21735381.