Oral lichen planus is an 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. The reason for this abnormal immune response is unknown.

Oral lichen planus is usually an ongoing (chronic) condition. Treatments that suppress the immune system abnormalities may improve more severe lesions and lessen pain.  People with oral lichen planus may also have related lichen planus lesions on the skin, genitals or other parts of the body.