Diagnosis: Lichen Planus
Lichen planus is a common inflammatory condition involving the skin, nails, mucous membranes, and hair follicles. It has no racial predilection, and often affects men and women aged 20-60 years. It is less common in children, who account for only 4% of cases. The lesions are often atypical.
Clinically, patients often present with erythematous to violaceous small, flat-topped, polygonal papules that may coalesce into plaques. Lesions are generally pruritic, and may be tender or painful. Older lesions may be hyperpigmented. White streaks known as Wickham striae can cross the surface of lesions. These striae also can be present orally, such as in the patient described here. Oral lesions also may be atrophic or erosive.
Common body locations with involvement are the inner wrists, legs, torso, or genitals (glans penis). The face is rarely involved. Nail changes, such as longitudinal ridging and splitting, onycholysis, red lunula, yellow nail syndrome, and pterygium formation, can occur.
Lichen planus often spontaneously resolves on its own, with 2/3 of patients resolving in a year. Mucous membrane disease tends to be more chronic. The etiology of lichen planus is unknown. It may have an autoimmune mechanism in which T cells induce keratinocytes to undergo apoptosis. Between 4% and 60% of lichen planus patients also have hepatitis C infections. The differential diagnosis for cutaneous lesions include lichenoid drug eruption, guttate psoriasis, syphilis, and pityriasis lichenoides et varioliformis acuta. Oral lesions may resemble candidiasis, leukoplakia, malignancies, and bullous disease.
Topical and intralesional steroids are often effective for localized disease. Systemic corticosteroids can be useful when lesions are widespread. Phototherapy, isotretinoin, acitretin, hydroxychloroquine, and oral immunosuppressive agents (such as cyclosporine and mycophenolate mofetil) all have been described in the treatment of lichen planus.