Oral lichen planus (LIE-kun PLAY-nus) is an ongoing (chronic) inflammatory condition that affects mucous membranes inside your mouth. Oral lichen planus may appear as white, lacy patches; red, swollen tissues; or open sores. These lesions may cause burning, pain or other discomfort.
Oral lichen planus can't be passed from one person to another. The disorder occurs when the immune system mounts an attack against cells of the oral mucous membranes for unknown reasons (autoimmune disorder).
Symptoms can usually be managed, but people who have oral lichen planus need regular monitoring because they may be at risk of developing mouth cancer in the affected areas.