Lichen planus, a recurring itchy disease, starts as a rash of small, separate, red or purple bumps that then combine and become rough, scaly patches.
The cause is unknown but may be a reaction to certain medications or possibly hepatitis B or C infection.
Typical symptoms include an itchy rash made of red or purple bumps that form into scaly patches appearing on different parts of the body and sometimes in the mouth or on the genitals.
Medications that may be causing lichen planus should be avoided.
This disease can last for more than 1 year, and it can recur.
Lichen planus of the mouth may occur in some people who have hepatitis B, have received the hepatitis B vaccine, have hepatitis C (see table The Hepatitis Viruses), or have the liver disorder primary biliary cholangitis.
Symptoms of Lichen Planus
The rash of lichen planus almost always itches, sometimes severely.
The bumps usually have angular borders and appear more purple on light skin and more brown on dark skin. When light is directed at the bumps from the side, the bumps display a distinctive sheen. New bumps may form wherever scratching or a mild skin injury occurs.
Sometimes a dark discoloration remains after the rash heals (called hyperpigmentation).
Image courtesy of Karen McKoy, MD.
Usually, the rash is evenly distributed on both sides of the body—most commonly on the torso, on the inner surfaces of the wrists, on the legs, and on the genital area. The face is less often affected. On the legs, the rash may become especially large, thick, and scaly. The rash sometimes results in patchy baldness on the scalp.
Lichen planus is not common among children.
About half of people who get lichen planus also develop it in the mouth. Lichen planus in the mouth usually results in lacy, bluish white lines and branches (called Wickham striae). This type of mouth patch often does not hurt, and the person may not know it is there. However, sometimes painful sores form in the mouth, which often interfere with eating and drinking.
In women, lichen planus often affects the vulva and vagina. Up to 50% of women who have lichen planus of the mouth have undiagnosed lichen planus of the vulva. In men, lichen planus commonly affects the genitals, especially the head of the penis.
Lichen planus affects the nails in up to 10% of cases. Some people may have only mild symptoms such as discoloration of the nail beds, thinning of the nails, and formation of nail ridges. Other people may completely lose their nails and have scarring from the cuticle at the base of the nail (the nail fold) to the skin under the nail (the nail bed).
Diagnosis of Lichen Planus
A doctor's evaluation
Skin biopsy
Doctors typically base the diagnosis of lichen planus on how the rash looks and where it appears on the body. However, because many other disorders can look like lichen planus (such as lupus erythematosus on the skin and candidiasis or leukoplakia in the mouth or vagina), doctors typically do a biopsy (examination of tissue under a microscope).
Once diagnosed, doctors may do other liver tests and tests for hepatitis B and C infections.
Treatment of Lichen Planus
Measures to relieve itching
Corticosteroid injections, pills, or lotions
Phototherapy
Measures to relieve mouth pain
People who have no symptoms do not need treatment. Medications that may be causing lichen planus should be stopped and avoided.
Lichen planus on the skin
Standard treatments can be used to relieve itching (see treatment of itching).
Phototherapy (exposure to ultraviolet light), sometimes combined with the use of psoralens (drugs that make the skin more sensitive to the effects of ultraviolet light) may also be helpful (see sidebar Phototherapy: Using Ultraviolet Light to Treat Skin Disorders). Combining ultraviolet A light with psoralens is called PUVA (psoralen plus ultraviolet A). Use of a small band of ultraviolet B light is called narrowband ultraviolet light B (NBUVB).
Lichen planus in the mouth
Lidocaine mouthwashes should not be used more frequently than prescribed.
Other treatment options include corticosteroid ointments, injections, or pills.
Prognosis for Lichen Planus
Lichen planus usually clears up by itself after 1 or 2 years, although it sometimes lasts longer, especially when the mouth is involved. Prolonged treatment may be needed during outbreaks of the rash. However, between outbreaks, no treatment is needed.
People with painful mouth sores rarely develop oral cancer, but the rash on the skin does not turn cancerous. Mouth sores usually last for life.
Lichen planus in the vagina or vulva may be chronic and hard to treat, which decreases quality of life and may cause scarring.
