Lichen Planus

Definition

Lichen planus is a skin condition of unknown origin that produces small, shiny, flat-topped, itchy pink or purple raised spots on the wrists, forearms or lower legs, especially in middle-aged patients.

Description

Lichen planus affects between 1-2% of the population, most of whom are middle-aged women. The condition is less common in the very young and the very old. The lesions are found on the skin, genitals, and in the mouth. Most cases resolve spontaneously within two years. Lichen planus is found throughout the world and is equally distributed among races.

Causes and symptoms

No one knows what causes lichen planus, although some experts suspect that it is an abnormal immune reaction following a viral infection, probably aggravated by stress. The condition is similar to symptoms caused by exposure to arsenic, bismuth, gold, or developers used in color photography. Occasionally, lichen planus in the mouth appears to be an allergic reaction to medications, filling material, dental hygiene products, chewing gum or candy.

Symptoms can appear suddenly, or they may gradually develop, usually on the arms or legs. The lesions on the skin may be preceded by a dryness and metallic taste or burning in the mouth.

Once the lesions appear, they change over time into flat, glistening, purple lesions marked with white lines or spots. Mild to severe itching is common. White, lacy lesions are usually painless, but eroded lesions often burn and can be painful. As the lesions clear up, they usually leave a brown discoloration behind, especially in dark skinned people.

Lichen planus in the mouth occurs in six different forms with a variety of symptoms, appearing as lacy-white streaks, white plaques, or eroded ulcers. Often the gums are affected, so that the surface of the gum peels off, leaving the gums red and raw.

Diagnosis

A doctor can probably diagnose the condition simply from looking at the characteristic lesions, but a skin biopsy may be needed to confirm the diagnosis.

Treatment

Treatment is aimed at easing symptoms. Itching can be treated with steroid creams and oral antihistamines. Severe lesions can be treated with corticosteroids by mouth, or combinations of photochemotherapy (PUVA) and griseofulvin.

Patients with lesions in the mouth may find that regular professional cleaning of the teeth and conscientious dental care improve the condition. Using milder toothpastes instead of tartar control products also seems to lessen the number of ulcers and makes them less sensitive.

Prognosis

While lichen planus can be annoying, it is usually fairly benign and clears up on its own. It may take months to reach its peak, but it usually clears up within 18 months.

KEY TERMS

PUVA— A type of phototherapy that combines the oral or topical photosensitizing chemical psoralen, plus long-wave ultraviolet light-A (UVA).

Resources

OTHER

Lichen Planus Self-Help. Baylor College of Dentistry. 〈http://www.tambcd.edu/lichen〉.

Lichen planus

Lichen planus is a skin rash characterized by small, flat-topped, itchy purplish raised spots on the wrists, arms, or lower legs. Although the evidence is not conclusive, many researchers assert that Lichen planus is an autoimmune disease.

Lichen planus affects approximately one to two percent of the population. Although there is no apparent correlation to race or geographic region, it is interesting to note that the majority of individuals affected are women, age 30 to 50 years. Lichen planus rashes may produce discoloration of the skin, especially in darker skinned population groups. Lichen planus lesions may develop on the genitals or in the mouth. Within a few years, most of the spots disappear, even without treatment.

Although not definitive, researchers assert Lichen planus exhibits many of the characteristics of an autoimmune disorder. Autoimmune diseases result when the immune system attacks the body's own cells, causing tissue destruction. Dermatologists argue that the condition may result from a viral infection that is then aggravated by stress. Lichen planus symptoms are similar to allergic reactions to arsenic, gold, and bismuth. The spots are also similar to the type produced from allergic reactions to certain chemicals used to develop film.

There is a correlation (a statistical relationship) between allergic reactions to certain medications and the appearance of a Lichen planus rash in the mouth. Oral lichen planus usually forms white lines and spots that may appear in clusters. Only a definitive biopsy can fully distinguish the rash from yeast infections or canker sores. Dentists find that some patients develop a Lichen planus rash following dental procedures. Other reports indicate that a Lichen planus rash may appear as an allergic-reaction like response to certain foods, candy, or chewing gum.

Because the exact cause of Lichen planus is unknown, there is no specific treatment for the rash. Treatment with various combinations of steroid creams, oral corticosteroids, and oral antihistamines appears effective at relieving discomfort caused by the rash. In more severe cases PUVA photochemotherapy, a procedure where cells are photosensitizing and then exposed to ultraviolet light and antibiotics .

Lichen planus may also affect the growth of nails and, if present on the scalp, may contribute to hair loss.

Lichen planus is not an infectious disease. Research also indicates that it is not, as once argued, caused by any specific dietary deficiency.

See also Autoimmunity and autoimmune diseases; Viruses and responses to viral infection; Yeast, infectious