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.
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.
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 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.
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.
— A type of phototherapy that combines the oral or topical photosensitizing chemical psoralen, plus long-wave ultraviolet light-A (UVA).
Lichen Planus Self-Help. Baylor College of Dentistry. http://www.tambcd.edu/lichen.
1. any of certain plants formed by the mutualistic combination of an alga and a fungus.
2. any of various papular skin diseases in which the lesions are typically small, firm papules set very close together.
a condition characterized by localized cutaneous amyloidosis
) a condition resembling myxedema but unassociated with hypothyroidism, marked by mucinosis
and a widespread eruption of asymptomatic, soft, pale red or yellowish, discrete papules.
lichen ni´tidus a usually asymptomatic chronic inflammatory eruption consisting of numerous glistening, flat-topped, discrete, smooth, commonly skin-colored micropapules, located most often on the penis, lower abdomen, inner thighs, flexor aspects of the wrists and forearms, breasts, and buttocks. Widespread involvement may produce confluence of the lesions, with formation of scaly plaques.
lichen planopila´ris a variant of lichen planus characterized by formation of cone-shaped horny papules around the hair follicles, in addition to the typical lesions of ordinary lichen planus.
lichen pla´nus an inflammatory skin disease with wide, flat, purplish, shiny papules in circumscribed patches; it may involve the hair follicles, nails, and buccal mucosa; called also lichen ruber planus.
lichen ru´ber monilifor´mis a generalized or localized eruption with either round, dome-shaped, waxy, dark or bright red papules, or waxy, yellow, milia-like papules, often forming a moniliform (string-of-beads) pattern, sometimes arranged in keloidal bands. Some authorities consider the condition to be a variant of lichen simplex chronicus.
lichen sclero´sus (lichen sclero´sus et atro´phicus) a chronic atrophic skin disease marked by white papules with an erythematous halo and keratotic plugging. It sometimes affects the vulva (kraurosis vulvae) or penis (balanitis xerotica obliterans).
lichen scrofuloso´rum (lichen scrofulo´sus) a form of tuberculid manifested as an eruption of clusters of lichenoid papules on the trunk of children with tuberculous disease.
lichen sim´plex chro´nicus dermatosis
of psychogenic origin, marked by a pruritic discrete, or more often, confluent lichenoid papular eruption, usually confined to a localized area. Mechanical trauma, such as scratching or rubbing the area, is a factor in its development. The lesions may arise from normal skin or they may occur as a complication of other forms of dermatitis
. Called also circumscribed or localized neurodermatitis and lichen chronicum simplex.
Treatment consists of administration of corticosteroids applied locally as a cream or given by intralesional injection to relieve the pruritus. The area should be protected by light dressings and the patient encouraged to avoid mental stress, emotional upsets, and irritation of the affected area. The application of very hot or very cold compresses may afford temporary relief of the itching. The condition tends to become chronic with unexplained remissions and reappearance of lesions in a different part of the body.
lichen spinulo´sus a condition in which there is a horn or spine in the center of each hair follicle; called also lichen pilaris.
lichen stria´tus a self-limited condition characterized by a linear lichenoid eruption, usually in children.