Lichen Planus is a rare, recurrent, itchy rash or area of inflammatory eruptions (lesions) of unknown origin characterized by shiny reddish-purple spots on the skin and gray-white ones in the mouth. The disorder may present as itchy spots on the wrist, legs, torso, genitals, mouth, or lips. The eruptions may appear as small separate, angular spots that may coalesce into rough scaly patches. This disorder is frequently accompanied by oral lesions of the mucous membranes that line the mouth. The disorder affects women more frequently than men.
The symptoms of Lichen Planus may begin abruptly or gradually. The initial attack may persist for weeks or months; intermittent recurrences may occur for years. The primary spots are 2 to 4 mm in diameter with angular borders, a violet color and a distinct sheen in cross-lighting. Rarely, blisters may develop. Moderate to severe itching may be present which frequently fails to respond to treatment.
The lesions are usually distributed symmetrically, most commonly on the joint surfaces of the wrists and on the legs, palms and soles, trunk, glans penis, and mucous membrane of the mouth, anus, and vagina. Lesions are occasionally generalized, but the face is rarely involved. The lesions may become large, scaly and warty (Hypertrophic Lichen Planus), particularly on the lower legs. During the acute phase, new spots may appear along a site of minor skin injury such as a superficial scratch (Kobner’s Phenomenon). Sometimes atrophy of the skin may develop as lesions persist. Some patients experience an absence of sweating (anhidrosis).
In Americans of Caucasian descent, an unusual darkening of the skin (Hyperpigmentation) may occur. In Americans of African descent, sometimes an unusual lack of skin color (Hypopigmentation) has been seen.
Although not common, hair loss may be among the consequences of Lichen Planus. When and if hair loss does occur, it involves small patchy areas of the scalp (atrophic cictrical alopecia).
Between 30 and 70 percent of patients show symptoms involving the mucosal membrane of the mouth. Oral symptoms often occur before skin lesions develop. The mucous membranes of the cheek, tongue margins and areas without teeth show asymptomatic, ill-defined, bluish-white, lacy lesions. Oral symptoms, consisting of a dryness and metallic taste or burning in the mouth, may appear first and may be the only evidence of the disease.
Chronic increases in severity and remissions are common.
The cause of Lichen Planus is not known. The initial occurrence may persist for weeks or months, and recurrences can continue over many years.
Some metals such as arsenic, bismuth, gold, or exposure to certain chemicals used in developing color-photographs, may cause an eruption indistinguishable from Lichen Planus. Quinacrine (Mepacrine) taken for a long period of time may produce Lichen Planus of the lower legs, as well as other dermatological and systemic disturbances. Some other drugs, among many, that may cause Lichen Planus-like eruptions are thiazide diuretics, topical beta-blockers, antimalarials, and phenothiazines. It is uncertain if there is a genetic predisposition to the disorder.
Lichen Planus affects 6 to 7 times more females than men. For the majority of individuals, onset usually occurs around 40 to 50 years of age; however, cases have been described in individuals between 30 to 60 years of age. In rare cases, children may be affected.
Asymptomatic Lichen Planus does not require treatment. If a drug or chemical is suspected to be the cause, its use should be discontinued. In symptomatic Lichen Planus, antihistamines may help to decrease itching. Localized itchy areas may be treated with triamcinolone acetonide suspension diluted with saline and superficially injected into the lesion; it may also be treated with corticosteroid drugs. Tretinoid solution may also be beneficial in treating Lichen Planus. For oral lesions, viscous lidocaine mouthwashes before meals and triamcinolone acetonide in emollient dental paste may be helpful.
Erosive oral lesions and widespread itchy skin lesions often require the use of a systemic corticosteroid (e.g., oral prednisone). Unfortunately, skin lesions may return after systemic prednisone has been discontinued. In this case, continued low dosage of a systemic corticosteroid may be instituted.
Photochemotherapy with 8-methoxypsoralen and long-wave ultraviolet light (PUVA) is used as a therapy for cutaneous and oral lichen planus.
New drugs and treatments are tested in the form of clinical trials sponsored by the National Institutes of Health or by companies within the pharmaceutical industry. The reports of some recent clinical trials are summarized below.
In a study comparing the results of the treatment of lichen planus with the topical application of each of two steroids, clobetasol treatment resolved 75 percent of the lichen planus lesions and flucinonide resolved 25 percent. In each case, the glucocorticoid treatment was accompanied by antifungal mouthwashes. Further research is needed to determine the long-term safety and effectiveness of clobetasol as a treatment for lichen planus.
In another study comparing the efficacy of the corticosteroids mesalazine and clobetasol,
the authors concluded that “If confirmed by further investigations, … mesalazine might be considered an alternative to clobetasol.”
Since patients often have difficulty applying topical steroids to the innner lining of the mouth, especially if large areas must be covered, an aqueous mouthwash of hydrocortisone was tested on 102 patients with oral lichen planus (OLP) in an open clinical efficacy study with positive results.
Further research is needed to determine the long-term safety and effectiveness of these investigational therapies for lichen planus.
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