Inflammatory, pruritic disease of the skin and mucous membranes, which can be either generalized or localized; characterized by distinctive purplish, flat-topped papules having a predilection for the trunk and flexor surfaces; lesions may be discrete or coalesce to form plaques.

Lichen planus (LP) is a chronic inflammatory and autoimmune disease that affects the skin, nails, hair, and mucous membranes. It is not an actual lichen, but is named for its appearance...