Primary cicatricial alopecias (PCAs), rare disorders that lead to permanent hair loss, have been poorly understood and are difficult to treat. Lichen planopilaris (LPP)is a prototypical PCA; patients often present with sudden onset of hair loss and clinically significant symptoms of itching, burning, and pain of the scalp. Examination reveals patchy alopecia or a more diffuse thinning of the scalp with characteristic perifollicular erythema and perifollicular scale at the margins of the areas of alopecia.Treatment typically includes use of antiinflammatory medications; although symptoms may improve,hair loss is often progressive.