Cicatricial (scarring) alopecias: an overview of pathogenesis, classification, diagnosis, and treatment

Abstract

Cicatricial (scarring) alopecia forms a group of disorders in which the common final pathway is the destruction of the hair follicle unit that is replaced by fibrous tissue. Hair loss may occur as a primary event when the follicle is the main target of the disease process (primary cicatricial alopecias) or as a secondary event when the follicle act as an 'innocent bystander' in the course of a disease occurring outside of the follicular unit (secondary cicatricial alopecias). Permanent hair loss may also occur in the late phases of some nonscarring alopecias that are called 'biphasic alopecias.' Primary cicatricial alopecia accounts for 5% of all trichologic consultations at the Section of Dermatology, University of Genoa, Genoa, Italy. Considering that hair loss has a strong impact on patients' psychology and quality of life, and that cicatricial alopecias can be associated with underlying systemic implications, it is extremely important that every clinician is familiar with the diagnosis and treatment of the different types of cicatricial alopecia. An accurate clinical assessment integrated with (video) dermatoscopy and histopathologic studies permits a high standard performance of correct diagnoses. A brief review of our current knowledge of disease pathogenesis and the hypothetical disease mechanisms is presented. Some practical considerations for improving the 2001 North American Hair Research Society working classification of the primary cicatricial alopecias are suggested. The aim of treatment is to slow or stop the progression of the inflammatory waves and the scarring process at the earliest phase of involvement. Recommendations for therapy are based upon a literature review, personal experience, expected adverse effects, and some pragmatic considerations such as the cost and patient compliance.