What causes lichen planus?
The cause is not known, but it may be an autoimmune disease, which causes the immune system to mistakenly attack the body. A rare type of lichen planus (familial bullous) runs in families.
It’s important to get an accurate diagnosis because other conditions can look like lichen planus. Diuretics, used to treat heart disease, and medicines that prevent malaria can cause a similar rash. Many people with a hepatitis C virus infection also have lichen planus. Although it’s very rare, a metal filling may be the cause or oral lichen planus. Replacing it with a non-metal filling usually stops the lichen planus.
Although anyone can develop lichen planus, it’s most common in middle-aged people. Women develop oral lichen planus more frequently than men. Certain conditions can trigger a lichen planus outbreak, including:
Oral lichen planus can be triggered by mouth injury, infections or something the person is allergic to such as dental materials. Stress can cause it to get worse or recur.