摘要： The persistent discolouration in lichen planus pigmentosus is secondary to persistent melanophages in superficial dermis in these patients. We evaluated the effect of Q-switched Nd-YAG laser on the clinical, pigmentary and immunological markers in the patients with lichen planus pigmentosus. Nine females with a clinical diagnosis of lichen planus pigmentosus were included in the study. After six sessions of laser with toning protocol, performed over a representative area of 5x5 cm2 at 2-weekly intervals, the mean clinical improvement as per the physician assessment was 25.7% (10-40%). There was no significant reduction in melanin and erythema index. On expression analysis using reverse transcriptase polymerase chain reaction, the reduction in tyrosinase (p=0.03) was statistically significant, though, the reduction in other pigment and immunological markers was not significant. The immunohistochemistry quantification data of corresponding proteins also did not show any significant difference. Post inflammatory hypopigmentation was noted in one patient. Q-switched Nd-YAG laser toning protocol resulted in modest clinical and histological improvement in patients of lichen planus pigmentosus.