Lichen Planus

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Medical Author:

Gary W. Cole, MD, FAAD

Gary W. Cole, MD, FAAD

Dr. Cole is board certified in dermatology. He obtained his BA degree in bacteriology, his MA degree in microbiology, and his MD at the University of California, Los Angeles. He trained in dermatology at the University of Oregon, where he completed his residency.

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Medical Editor:

William C. Shiel Jr., MD, FACP, FACR

William C. Shiel Jr., MD, FACP, FACR

Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

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• 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.
• Lichen planus can be quite itchy.
• Lichen planus may spontaneously resolve.
• Lichen planus is managed with a variety of topical and oral medications.

Lichen planus is a chronic recurrent rash that is due to inflammation. 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 is a very curious and poorly understood skin condition. Its name is descriptive in that to some it resembles a simple plant, a lichen, that grows on rocks and tree bark, while planus is Latin for flat.

The cause of lichen planus is unknown. In certain locales, patients with extensive lichen planus seem to be more likely to have a hepatitis C virus infection of the liver. However, it is unclear if this virus is the cause of lichen planus in such situations.

Some drugs, such as those containing arsenic, bismuth, or gold, can produce an eruption which appears identical to lichen planus. Exposure to certain chemicals used in the development of color photographs can also produce a similar rash. The long-term use of the drugs quinacrine or quinidine (Quinidine Gluconate, Quinidine Sulfate), which is used for malaria, certain microscopic organisms, and worms, may produce hypertrophic lichen planus of the lower legs and other skin and body-wide (systemic) disturbances. Lichenoid eruptions can occur in graft-versus-host disease in people who have received bone marrow transplants. Tissue examination by a pathologist (biopsy) would be necessary distinguish lichenoid drug eruptions from classical lichen planus, which is not caused by medication. Of course, stopping the offending drug is associated with resolution of the eruption.