Lichen planus pigmentosus (LPP) is a pigmentary disorder characterized by persistent and asymptomatic slate-gray pigmentation over face, neck and flexures. This results in severe cosmetic disability and morbidity. Existing treatment options have shown minimal to nil improvement. The persistent pigmentation is secondary to persistent melanophages in the papillary dermis resistant to medical therapies. Q-switched Nd-YAG laser is known to disrupt the melanin pigment in the dermis via photothermolysis. We plan to undertake this pilot study to evaluate the effect of Q-switched Nd-YAG laser in the management of 10 patients of lichen planus pigmentosus. Six laser sessions will be performed at 2-weekly interval using a low fluence skin toning protocol. Patient and physician assessment of improvement as well as objective measurement of  melanin and erythema index will be done at each visit and 2 weeks after the last laser session. Since, there are no proper study available evaluating the effect of Nd-YAG laser in LPP, we also plan to study the laser induced changes in immunological and pigmentary markers pre and post treatment which will be done by analysis of immunohistochemistry and mRNA expression of melanin pigment markers as MART-1, MITF and tyrosinase and macrophage markers as CD68 and CD163. This will be done one hour after the first laser session in five patients and after 2-weeks of last laser session in remaining five patients.