Am Fam Physician. 2000;61(11):3327
See related article on lichen planus.
What is lichen planus?
Lichen planus is a skin disease. Men and women get it and it occurs in every race. While it may occur at any age, it usually affects middle-aged adults.
What does lichen planus look like?
Lichen planus looks like purple or reddish-purple bumps on the skin. The bumps have flat tops. They are uneven in shape. If you look at the bumps closely, you might see white scales or flakes on them. Lichen planus can appear on any area of the skin. The most common areas are the inner wrists, the forearms and the ankles.
Lichen planus may also affect the scalp, the nails or inside of the mouth. On the scalp, lichen planus may cause hair loss. Lichen planus of the nails can cause brittle or split nails. In the mouth, it looks like lacy white patches on the inside area of the cheeks. Sometimes lichen planus affects areas of skin where you had a cut or burn.
What causes lichen planus?
You can't “catch” lichen planus from someone else. You can't “give” it to someone else. 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.
How will it affect me?
Lichen planus usually causes itching. The itching can be mild or very bad. Sometimes the bumps don't itch, but this isn't usual.
You may have just a few small bumps or you may have a lot. After the bumps go away, they may leave a dark brown area on the skin. This is more likely to happen in persons of Asian, Hispanic or African heritage. These brown spots are not scars. They will slowly go away, but it may take many months.
How can I be sure I have lichen planus?
Only your doctor can tell if you have lichen planus. If you have reddish-purple bumps on the skin you should see your doctor. The doctor may want you to have blood tests or a skin biopsy. A small bit of skin is taken from one of the purple bumps. It is sent to a laboratory to see if it is lichen planus.
How is lichen planus treated?
There is no cure but medicine can help the itching and rash get better. Most of the time, the bumps go away without any treatment after about one year. You can get lichen planus more than one time. Treatment can make your skin look better. If lichen planus is only on a small part of your body, you can use a cream. These creams are applied directly to the bumps. Because these creams are strong medications, you should not put them on normal skin. You should be careful when putting the cream on your face, under your arms or on your genital area. If your itching is very bad, your doctor may suggest an antihistamine (say: ant-a-hist-a-mean) such as Benadryl.
If the bumps don't go away, or if you have many bumps, you may need stronger medicines. Your doctor may give you a medicine called prednisone (say: pred-ni-zone). It comes in shots or pills. Prednisone has many side effects, so take this medicine just as your doctor says. You could have light therapy, (also called PUVA) for lichen planus. It can be given in some doctors' offices. Or, you could take a pill with a retinoid in it. Retinoids have many side effects. You have to have regular blood tests while you take this medicine.
Lichen planus of the scalp must be treated fast or the hair may never grow back. Lichen planus inside the mouth may cause sores that hurt. It can be hard to eat because of these sores.