ABSTRACT
This chapter focuses on trichoscopy of primary cicatricial alopecias. Lichen planopilaris (LPP) is considered as a follicular form of lichen planus and affects mainly adults. It can present either as patchy or diffuse hair loss. The inflammatory process in LPP is mainly folliculocentric, so signs of disease activity will have a follicular or perifollicular pattern of distribution on the scalp. An interesting feature that is characteristic of LPP is that scaling may embrace hair follicles forming tubular structures, known as hair casts. Frontal fibrosing alopecia (FFA) affects mainly postmenopausal women and is characterized by a progressive band of alopecia of the frontal/frontotemporal scalp. Trichoscopy plays an important role in the differential diagnosis between FFA and other hair disorders that may affect the hairline, namely alopecia areata, traction alopecia, and androgenetic alopecia. Signs of disease activity in FFA are very similar to LPP, including perifollicular erythema and scaling.
