Philippe Assouly, MD, and Pascal Reygagne, MD
Lichen planopilaris (LPP), a follicular form of lichen planus, is a rare inflammatory lymphocyte mediated disorder. Although the physiopathology is unclear, an autoimmune etiology is generally accepted. Women are affected more than men, and the typical age of onset is between 40 and 60 years. LLP is a primary cicatricial alopecia whose diagnosis is supported in the early stage by both clinical and histopathological findings. Within the margins of the expanding areas of perifollicular violaceous erythema and acuminate keratotic plugs, the histology can show the lichenoid perifollicular inflammation. LPP can be subdivided into 3 variants: classic LPP, frontal fibrosing alopecia (FFA), and Lassueur Graham-Little Piccardi syndrome. With the exception of FFA, the hairless patches of the scalp can be unique or can occur in multiples and can present with a reticular pattern or as large areas of scarring. This condition can have major psychological consequences for the affected patients. The therapeutic management often is quite challenging, as relapses are common after local or systemic treatments. Further research is needed on the pathogenesis, and randomized controlled trials of treatment with scientific evaluation of the results are necessary to appreciate the proposed treatment.
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