Lichen Planus

Lichen planus is a chronic inflammatory and immune-mediated disease that affects the skin, nails, hair, and mucous membranes. It is not an actual lichen but is named for its appearance, and is characterized by polygonal, flat-topped, violet-colored papules and plaques with an overlying fine white scale, commonly affecting the backs of the hands, the wrists and forearms, the trunk, the lower legs, and the inside of the mouth. Although its clinical range is broad, the skin and oral cavity remain its major sites of involvement. The cause is unknown but is thought to be the result of an autoimmune process with an unidentified trigger, and there is no cure, though many medications and procedures are used to control its symptoms.