Lichen planus (LIE-kun PLAY-nus) is a condition of the skin, hair, nails, mouth and genitals. On skin, lichen planus often appears as purple, itchy, flat bumps that develop over several weeks. In the mouth and genital mucosa, lichen planus forms lacy white patches, sometimes with painful sores.

Mild lichen planus of the skin may not need treatment. If the condition causes pain or intense itching, you may need prescription medicine.

Symptoms of lichen planus vary depending on the part of the body affected. Nail disease usually affects several nails. Symptoms include:

• Purple, shiny, flat bumps, often on the inner forearms, wrists or ankles.
• Lines of rash where the skin has been scratched.
• Lacy white patches on the tongue or inside of the cheeks.
• Itchiness.
• Painful sores in the mouth or genitals.
• Rarely, hair loss.
• Nail scarring or loss.
• Dark lines from the tip of the nail to the base.

When to see a doctor

See your health care provider if tiny bumps or a rash appears on your skin for no known reason, such as contact with poison ivy. Also see your health care provider if you have any symptoms related to lichen planus of the mouth, genitals, scalp or nails.

It's best to get a prompt and correct diagnosis because a number of skin and mucous membrane conditions can cause sores and pain.

The cause of lichen planus is likely related to the immune system attacking cells of the skin or mucous membranes. It's not clear why this irregular immune response happens. The condition isn't contagious.

Lichen planus may be activated by:

• Hepatitis C infection.
• Pain relievers and other medicines.
• An allergic reaction to the metal in dental fillings.

Anyone can develop lichen planus. It most often affects middle-aged adults. Lichen planus in the mouth is more likely to affect women than men.

Lichen planus can be difficult to treat on the vulva and in the vagina. It can cause scarring and severe pain. Sores on the genitals can make sex painful.

The affected skin and nails might stay slightly darker even after healing.

Oral sores may affect your ability to eat. Oral lichen planus increases the risk of oral cancer. Rarely, lichen planus affects the ear canal. Left untreated, it may lead to hearing loss.

To find the cause of your illness, your health care provider will likely talk with you about your symptoms and medical history and do a physical exam. You may also need some tests. These might include:

• Biopsy. Your health care provider removes a small piece of affected tissue for examination in a laboratory. The tissue is examined to see if it has the cell patterns typical of lichen planus.
• Blood tests. You may have your blood drawn to test for health problems related to lichen planus. For example, hepatitis C.

If you have no pain or discomfort, you may not need any treatment. Lichen planus on the skin often clears up on its own in months to years.

Medicines and other treatments might help relieve itching, ease pain and speed healing. Talk with your health care provider to weigh the pros and cons of treatment options. You may need more than one approach to control your symptoms.

If the disease affects your mucous membranes and nails, it tends to be harder to treat. Even if treatment works, the symptoms may return. You'll likely need to visit your health care provider for follow-up care at least once a year.

Corticosteroids

Often, the first choice for treatment of lichen planus of the skin is a prescription corticosteroid cream or ointment. This may help ease pain, swelling and inflammation.

If a topical corticosteroid doesn't help and your condition is severe or widespread, your health care provider might suggest corticosteroid pills or injections.

Side effects vary, depending on the method of use. Corticosteroids are safe when used as directed.

Oral anti-infections drugs

Other oral medicines used for lichen planus are the antimalarial hydroxychloroquine (Plaquenil) and the antibiotic metronidazole (Flagyl, others).

Immune response medicines

For more-severe symptoms, you may need prescription medicine that changes your body's immune response. The following drugs have been used with some success but further study is needed:

• cyclosporine (Sandimmune).
• Azathioprine (Azasan).
• methotrexate (Trexall).
• mycophenolate (Cellcept).
• sulfasalazine.
• thalidomide (Thalomid).

Antihistamines

An antihistamine medicine taken by mouth might ease the itchy skin caused by lichen planus.

Light therapy

Light therapy may help clear up lichen planus affecting the skin. This approach is also called phototherapy. One method involves exposing the affected skin to ultraviolet B light 2 to 3 times a week for several weeks.

One possible side effect is lasting changes in skin color (postinflammatory hyperpigmentation) even after the skin heals.

Retinoids

Your health care provider might prescribe a retinoid medicine taken by mouth or applied to the skin. One example is acitretin.

Retinoids can cause birth defects, so this type of medicine isn't for people who are pregnant or may become pregnant. If you're pregnant or nursing, your health care provider may suggest that you delay treatment or choose a different treatment.

Dealing with triggers

If your health care provider thinks that your lichen planus is related to an infection, allergies, a medicine you take or some other trigger, you might need other treatment or tests to address that. For example, you may need to switch medicine or your health care provider may suggest additional testing for allergens.

Self-care steps can help reduce itching and pain caused by lichen planus. These include:

• Taking a bath in lukewarm water. Sprinkle in an oatmeal-based bath product (Aveeno, others). Rinse well, pat dry and apply a moisturizer.
• Applying a cool, damp cloth.
• Using the type of hydrocortisone cream or ointment that you can get at a store without a prescription. Get a product that has at least 1% hydrocortisone. Do this only if you aren't using a prescription corticosteroid product on your skin.
• Avoiding scratching your skin and injuring your nails.
• Brushing your teeth twice a day and flossing daily, if you have oral lichen planus.

A few small clinical trials have suggested the benefit of aloe vera gel for treating lichen planus of the vulva and aloe vera mouthwash for disease of the mouth.

Look into alternative medicine approaches that help reduce stress, as stress can worsen the symptoms of lichen planus.

Talk with your health care provider before trying an alternative treatment for lichen planus. Some alternative medicines or supplements have unwanted side effects.

You'll likely start by seeing your primary care provider. Or you may be referred to a doctor who specializes in skin diseases (dermatologist). If the condition affects the vulva or vagina, you may be referred to a specialist in conditions of the female reproductive system (gynecologist).

Here's some information to help you get ready for your appointment.

What you can do

Before your appointment make a list of:

• Symptoms you've been having and for how long.
• All medicines, vitamins and supplements you take, including the doses.
• Questions to ask your health care provider.

For lichen planus, some basic questions to ask your health care provider include:

• What's the most likely cause of my symptoms?
• Are there other possible causes?
• Do I need any tests?
• How long will these skin changes last?
• What treatments are available, and which do you recommend?
• What side effects can I expect from treatment?
• I have these other health conditions. How can I best manage them together?
• Are there any restrictions that I need to follow?
• Should I see a specialist?
• Is there a generic alternative to the medicine you're prescribing?
• Do you have any brochures or other printed material I can take with me? What websites do you recommend?

What to expect from your doctor

Your health care provider is likely to ask you a number of questions, such as:

• Where on your body have you noticed symptoms?
• Are the affected areas itchy or painful?
• Would you describe the pain as mild, moderate or severe?
• Have you recently started new medicines?
• Have you recently had immunizations?
• Do you have any allergies?