From hair colour to diagnosis

Hair pigmentation contributes extremely to the visual appearance and human-to-human communication, thus exerting enormous sexual and social impact. Follicular melanogenesis depends on genetic, biochemical and physical phenomena as well as proper epithelial-melanocytic interaction. Shades of grey, yellow, brown, red, and black produced by melanin define the exact determination of hair colour. Versatile clinical conditions depend on genetic melanogenetic changes, pigment transfer to bulb keratinocytes defects and impaired signal transduction pathways. Herein, an update of recent scientific advances on follicular melanogenesis and its pathological-driven compartmental changes reflecting specific disease phenotypes, are presented.