Diseases on hair follicles leading to hair loss part II: scarring alopecias.

In Part I of the review (July/August 2004), the anatomy of hair follicles, the diagnostic approach to diseases leading to hair loss, and nonscarring alopecias were discussed. In this article (Part II of II), the focus is on scarring alopecias (dissecting folliculitis, folliculitis decalvans, lichen planopilaris, lupus erythematosus) in regard to pathogenesis, clinical findings, and current options of treatment. Most important for the survival of the hair follicle are the epithelial stem cells within the follicular bulge that communicate with the fibroblasts of the dermal papilla. These structures may be destroyed by systemic autoimmune disorders as well as by granulomatous diseases. To prohibit permanent damage of hair follicles, early diagnosis and the correct treatment are necessary.