Lichen planus is a skin condition that causes itchy, flat-topped, and raised lesions on the skin or mucous membranes. The cause of lichen planus is unknown, but it is believed to be an autoimmune disorder in which the body’s immune system attacks the skin or mucous membranes. Lichen planus can occur anywhere on the body, but is most commonly found on the wrists, ankles, and lower back. The lesions may be red or purple, and can be accompanied by white streaks or bumps.
