A randomized trial assessing the effectiveness of different concentrations of isotretinoin in the management of lichen planus

The aim of our 10-year study was to test the effectiveness of topical therapy based on 0.18% isotretinoin, comparing it with that most frequently used, i.e. at 0.05% concentration. Seventy patients with an established diagnosis of oral lichen planus were involved in the study. The patients were randomly divided into two groups, and the drug was administered topically at 0.05% and 0.18% concentrations.The drug at the higher concentration, according to the same protocol, was administered to the patients who did not benefit from the therapy at the lower concentration. None of the cases of reticular lichen planus showed clinical or histological improvement. In contrast, the atrophic–erosive forms showed a significant improvement, both clinical and histological: in 26 patients (at 0.18% concentration) and in nine patients (at 0.05% concentration), the symptoms, as well as the erosions or ulcers observed, disappeared. The disappearance of dysplasic phenomena was observed at 0.18% concentration. Topical application of the drug was accompanied by an increase in soreness and pain, as well as greater sensitivity to hot foods. However, these side effects were transitory, and considered acceptable by the patients. The proposed therapeutic protocol was effective towards highly active atrophic–erosive oral lichen planus with dysplasic phenomena, which is the form of the disease at higher risk of malignant evolution.