dermatologic disorders
Lichen Planus
Symptoms and Signs of Lichen Planus
Typical lesions are pruritic, violaceous (purple), polygonal, flat-topped papules and plaques. Erythema may look more purple or brown on dark skin than on light skin. Lesions initially are 2 to 4 mm in diameter, with angular borders and a distinct sheen in cross-lighting. They are usually symmetrically distributed, most commonly on the flexor surfaces of the wrists, legs, trunk, glans penis, and oral and vaginal mucosae but can be widespread. The face is rarely involved. Onset may be abrupt or gradual. Children are affected infrequently. This image shows small papules with a sheen in cross-lighting typical of lichen planus. Image courtesy of Karen McKoy, MD. This image shows vesiculobullous lesions (some ruptured) resulting from lichen planus. Image courtesy of Karen McKoy, MD. This image shows papules and plaques resulting from lichen planus. Image courtesy of Karen McKoy, MD. This photo shows papules and plaques of lichen planus. Violaceous flat-topped papules are visible on the dorsal arm. Erythema may look more purple or brown on dark skin. Image courtesy of Karen McKoy, MD. This image shows violaceous flat-topped papules coalescing into plaques on the dorsal hand of a patient with lichen planus. Image provided by Thomas Habif, MD. During the acute phase, new papules may appear at sites of minor skin injury (Koebner phenomenon), such as a superficial scratch. Lesions may coalesce or change over time, becoming hyperpigmented, atrophic, hyperkeratotic (hypertrophic lichen planus), or vesiculobullous. Although pruritic, lesions are rarely excoriated or crusted. If the scalp is affected, patchy scarring alopecia (lichen planopilaris) may occur. The oral mucosa is involved in about 50% of cases; oral lesions may occur without cutaneous lesions. Reticulated, lacy, bluish white, linear lesions (Wickham striae) are a hallmark of oral lichen planus, especially on the buccal mucosae. Tongue margins and gingival mucosae in edentulous areas may also be affected. An erosive form of lichen planus may occur in which the patient develops shallow, often painful, recurrent oral ulcers, which, if long-standing, rarely become cancerous. Chronic exacerbations and remissions are common. Vulvar and vaginal mucosae are often involved. Up to 50% of women with oral mucosal findings have undiagnosed vulvar lichen planus. In men, genital involvement is common, especially of the glans penis. Nails are involved in up to 10% of cases. Findings vary in intensity with nail bed discoloration, longitudinal ridging and lateral thinning, and complete loss of the nail matrix and nail, with scarring of the proximal nail fold onto the nail bed (pterygium formation). 