Lichen planus is a skin rash that is triggered by the immune system. It is not known why the immune response occurs. There may be several contributing factors, and each case is different. Potential causes include:
Lichen planus is a chronic recurrent rash of unknown cause with no established cure. Lichen planus generally affects adults and can involve any portion of the body, but it has a predilection for the wrists, ankles, and oral and genital tissues.
The rash is characterized by small, flat-topped, many-sided (polygonal) bumps that can grow together into rough, scaly plaques on the skin. There may also be a rash in the lining (mucous membranes) of the mouth or vagina.
Lichen planus can be quite itchy. Lichen planus may spontaneously resolve.
Lichen planus is managed with a variety of topical and oral medications.