ABSTRACT
Scarring or cicatricial alopecias are a poorly understood group of inflammatory disorders that lead to permanent destruction of the pilosebaceous unit and permanent hair loss. Cicatricial alopecias have traditionally been separated into two categories: primary and secondary. In the primary group, the pilosebaceous unit is the target of the inflammatory attack that results in replacement of the follicle with fibrous tissue. In contrast, the secondary cicatricial alopecias encompass nonfollicular or external processes that can lead to follicular destruction as a by-product. Common examples of secondary cicatricial alopecias include physical injuries (radiation, thermal burns, traction, other scalp injuies), infiltrative processes (metastatic or localized tumors, sarcoidosis) and severe infection (kerion). The focus of this chapter is on primary cicatricial alopecias. Despite astounding strides forward in our understanding of hair
biology, the cicatricial alopecias until recently have been an “orphan” of the hair disorders, largely neglected in the clinical and research realm. Our challenge is to harness the knowledge we have gained in hair biology to improve our understanding of these incredibly devastating diseases that leave patients with permanent hair loss. Fortunately, progress is occurring, including efforts to clarify clinical and histologic classification of the diseases, to identify major research interests, and to translate research progress into new treatment options.
