Lichen planus is a mucocutaneousdisorder which involves various mucosal surfaces either alone or along with involvement of skin. It most commonly involves the oral mucosa when compared with other mucosal site. Lichen planus is believed to result from an abnormal T-cell-mediated immune response in which basal epithelial cells are recognized as foreign because of changes in the antigenicity of their cell surface.3 The cause of this immune-mediated basal cell damage is unknown. Likewise, it is unknown if lichen planus represents a single disease process or several closely related entities with similar clinical presentations. A recent immunologic comparison of 2 variants of OLP suggested that different immunopathogenic mechanisms might be involved.Lichen planus affects primarily middle-aged adults, and the prevalence is greater among women.Children are onlyrarely affected. The classic skin lesions of the cutaneousform of lichen planus can be described as purplish, polygonal, planar, pruritic papules and plaques. These skin lesions commonly involve the flexor surfaces of the legs and arms,especially the wrists.
