The Pathogenesis of Primary Cicatricial Alopecias

The document from November 2010 reviews the pathogenesis of primary cicatricial alopecias (PCAs), which are disorders causing permanent hair loss due to the destruction of hair follicle stem cells, often linked to autoimmune disease. It discusses the classification of PCAs based on inflammatory cells and the lack of understanding of the signaling pathways leading to immune attacks on hair follicle stem cells. The review emphasizes the need for further research to develop effective treatments and to understand the immunopathology of epithelial stem cells. It also explores the role of immune privilege collapse, CD200 expression loss, cell-mediated cytotoxicity, proinflammatory responses, apoptosis, sebaceous gland dysfunction, and PPARγ deficiency in PCA pathogenesis. The document suggests that PPAR-γ agonists may be promising for PCA therapy and highlights the potential role of environmental triggers, genetic factors, and stress-induced inflammation in PCA development. It concludes with a call for more attention to PCAs from researchers to improve diagnosis and treatment, and suggests a potential reclassification of PCAs based on molecular pathways.