Although lichen planus is a well-characterized dermatologic condition affecting skin, mucosa, hair and nails, treatment is often disappointing and even controversial. The varied manifestations of lichen planus result in markedly different clinical courses, which makes treatment planning extremely challenging. Spontaneous remissions occur more frequently with cutaneous lichen planus than with oral lichen planus. The mean duration of oral lichen planus is about five years, but the erosive form does not spontaneously resolve. Faced with the reported clinical variances of lichen planus, Cribier and associates performed a database review to evaluate treatment recommendations.

There are no large prospective trials with definitive results of the efficacy of various drug and treatment regimens. The largest controlled series included 65 patients. The authors selected 83 clinical trials and also analyzed case reports and review articles. The cutaneous and oral forms of lichen planus were examined separately. The criteria defined by Sackett were applied to establish the level of proof of effectiveness (levels A, B and C). Level A indicates large randomized controlled trials that allow definitive conclusions. Clinical trials with rigorous methods in which small numbers of patients were included are classified as level B. Controlled trials with less than 20 patients in each group were classified as level C, as well as trials without randomized controls.

The accompanying table summarizes the main published results. The authors' review demonstrated that there were no level A trials. The remainder of the controlled trials displayed disappointing results because of various methodological deficiencies, such as low numbers of subjects, faulty analysis of data or observational retrospective data. Many of the studies lacked precise clinical data and none of the studies used a quality-of-life scale; therefore, meta-analysis wasn't possible. The authors chose to consider only controlled studies in an attempt to define therapeutic indications using evidence-based analysis.

The first-line therapy in cutaneous lichen planus is acitretin. All other treatment methods or drugs are of uncertain efficacy. Based on clinical experience, systemic corticosteroids are recommended by many authors and could be classified as second-line treatment for cutaneous lichen planus. All other treatments, mainly psoralen followed by ultraviolet A (PUVA) light therapy and griseofulvin, need to be studied more rigorously and are not recommended at this time.

The first-line therapy in oral lichen planus (accepted in most reviews) is topical corticosteroids. No other therapy demonstrated convincing superiority over these agents. Second-line therapy in plaque-like lichen planus should be topical retinoids or etretinate; however, strong evidence in their support is lacking. All other therapies are unapproved or of uncertain or doubtful efficacy. In severe, multiple–drug-resistant cases, topical cyclosporine could be recommended as a third-line treatment.

The authors conclude that their review demonstrated a lack of clear-cut results in the treatment of lichen planus, even for drugs that have been considered standard for some time. The promising newer therapies, such as topical cyclosporine, extracorporeal photo-chemotherapy or retinoids plus PUVA therapy, need to be tested in large controlled studies before widespread recommendations can be made.

editor's note: This article was part of a series presented in the Archives of Dermatology addressing evidence-based analysis of common dermatologic therapies. This particular analysis of the literature points out how difficult it is to base clinical management on definitive data based on efficacy of therapy. Even though lichen planus is not the most common dermatologic disease, it may be associated with substantial morbidity and altered quality of life. After withdrawal of drug therapy, the recurrence rate is substantial.—b.a.