<unk>  <unk>  is a chronic inflammatory and immune-mediated disease that affects the skin, nails, hair, and mucous membranes. It is not an actual lichen, and is only named that because it looks like one. It is characterized by polygonal, flat-topped, violaceous papules and plaques with overlying, reticulated, fine white scale (Wickham's striae), commonly affecting dorsal hands, flexural wrists and forearms, trunk, anterior lower legs and oral mucosa. Although there is a broad clinical range of<unk>  manifestations, the skin and oral cavity remain as the major sites of involvement. The cause is unknown, but it is thought to be the result of an autoimmune process with an unknown initial trigger. There is no cure, but many different medications and procedures have been used in efforts to control the symptoms. The term lichenoid reaction (lichenoid eruption or lichenoid lesion) refers to a lesion of similar or identical histopathologic and clinical appearance to<unk>  (i.e., an area which resembles<unk> , both to the naked eye and under a microscope). Sometimes dental materials or certain medications can cause a lichenoid reaction. They can also occur in association with graft versus host disease.
Lichen planus
Geographic tongue
Lichen nitidus
Leukoplakia
Lichen simplex chronicus
Lichen myxedematosus
Lichen sclerosus
Tinea barbae