Lichen planus is a skin disease that causes inflammation, itching, and skin lesions.

What is going on in the body?

Lichen planus is a skin disorder that produces scaly, purplish bumps with white lines or spots. It is thought to be an autoimmune disorder, or one in which the person produces antibodies against his or her own tissues. This abnormal immune response may be triggered by a viral infection. Lichen planus develops slowly and usually goes away in 18 months. However, in some people, it may last for many years.

What are the causes and risks of the condition?

Lichen planus is thought to be an autoimmune disorder that may be triggered by a viral infection. This disorder may develop after exposure to certain medications, dyes, and chemicals, including:

New research findings suggest that autoimmune disorders may be triggered by a transfer of cells between the fetus and the mother during pregnancy. The study involved women with scleroderma, an autoimmune disorder involving the skin. These women have more fetal cells in their blood decades after a pregnancy than women who don't have scleroderma. While further research is needed to substantiate these findings, the study does offer an explanation for the much higher incidence of autoimmune disorders in women than in men.