A chronic, atrophic skin disease characterized by white, angular, flat, well-defined, indurated papules with an erythematous halo and follicular, black, keratotic plugs. It is the most common cause of VULVAR LICHEN SCLEROSUS in females and balanitis xerotica obliterans in males. It is called also white spot disease and Csillag's disease. (Dorland, 27th ed).