It is not caused by stress, but sometimes stress makes it worse. Some cases may be linked to a virus called hepatitis C virus. This virus can cause liver disease. Hepatitis C virus infection can be passed through blood transfusions, unprotected sex or sharing infected needles. Because it may not cause any symptoms, your doctor may need to order a blood test to check for it.
Some medicines can cause lichen planus.
It is important to tell your doctor all the medicines you are taking. Many times the cause of lichen planus can't be found. Lichen planus usually causes itching. The itching can be mild or very bad. Sometimes the bumps don't itch, but this isn't usual.