Lichen planus is a benign, common disease that affects the skin, nails, and/or mouth. It affects about 1% of the general population. To understand what lichen planus (LP) is, it's important to note what the disease is not. Lichen planus is not an infectious disease. It is impossible to "catch" lichen planus from someone who has it or to give it to someone else. The disease is not a form of cancer, it does not appear to be inherited, and it is not related to nutrition.
Lichen planus is an inflammatory disease of unknown cause. There are cases of lichen planus-type rashes occurring as allergic reactions to medications for high blood pressure, heart disease and arthritis. In those cases, identifying and stopping the use of the drug helps clear up the condition within a few weeks. Some people with lichen planus can also have hepatitis C and your dermatologist may want to check you for this. Lichen planus affects men and women equally, and occurs most often in middle-aged adults.
Lichen planus of the skin is characterized by small, reddish-purple, flat-topped bumps that may be itchy. It can be anywhere on the body, but seems to favor the wrists and ankles. Thick patches may occur, especially on the shins. Blisters are rare. While the typical appearance of lichen planus makes the disease somewhat easy to identify, a skin biopsy may be needed to confirm the diagnosis. Sometimes, lichen planus of the skin causes few problems and needs no treatment. Most cases of lichen planus go away within two years. As lesions heal, they may leave a dark brown discoloration of the skin. Like the bumps themselves, these stains usually fade with time without treatment.
There is no known cure for lichen planus, but treatment can help control the lesions and relieve itching. Since every case of lichen planus is different, no one treatment is perfect. The two most common treatments include the use of topical corticosteroid creams and antihistamines. Both help the itching. More severe cases of lichen planus may require stronger medications such as steroids by mouth or phototherapy (light box therapy).
Lichen planus of the mouth most commonly affects the inside of the cheeks, gums and tongue. Oral lichen planus is more difficult to treat and typically lasts longer than skin lichen planus. Fortunately, many cases of lichen planus of the mouth cause minimal problems. About one in five people who have oral lichen planus also have skin lichen planus. Oral lichen planus typically appears as patches of fine white lines and patches inside the mouth. More severe forms of oral lichen planus can cause painful sores in the mouth or discomfort (burning) when eating certain foods. A biopsy of affected tissue may be needed to confirm the diagnosis of lichen planus.
There have been cases of lichen planus-type allergic reactions to dental materials but they are very rare. When an allergy by dental material has been proven, removing dental material is recommended. There is no known cure for oral lichen planus although there are many treatments that eliminate the pain of sores. When the disease causes no pain or burning, treatment may not be needed. Symptomatic lichen planus can be treated with a variety of medications, both applied to the sores (topical) and taken by mouth (oral). As with any disease of the lining of the mouth, lichen planus can lead to poor dental hygiene and gum disease. Regular visits to the dentist for examinations and cleaning at least twice a year are recommended.
Patients with oral lichen planus may be at a slightly increased risk of developing oral cancer. Because of this increased risk, the American Academy of Dermatology recommends discontinuing the use of alcohol and tobacco products, which also increase the risk of oral cancer. Regular visits to the dermatologist - every six to twelve months - for oral cancer screening are also recommended.
Spicy foods, citrus juices, tomato products, caffeinated drinks like coffee and cola, and crispy foods like toast and corn chips can aggravate oral lichen planus, especially if there are open sores in the mouth.
About one in five women with oral lichen planus will have lichen planus in the vaginal area. If it is mild, vaginal lichen planus may cause no problems, but red areas or open sores may cause pain, especially with sexual intercourse. Lichen planus of the genitals is much less common in men.
Nail changes may occur in lichen planus. The majority of nail changes result from damage to the nail matrix, or nail root. Usually only a few fingernails or toenails are involved, but occasionally all nails are affected. Nail changes associated with lichen planus include longitudinal ridging and grooving, splitting, thinning and nail loss. In severe cases, pterygium may develop and the nail may be temporarily or permanently destroyed.
In rare cases, lichen planus can affect the scalp. This is called lichen planopilaris, and can lead to redness, irritation, scarring, inflammation, and in some cases, permanent hair loss.