Segmented heterochromia in black scalp hair associated with iron-deficiency anemia. Canities segmentata sideropaenica.

A newly recognized disorder of black scalp hair is characterized by the irregularly alternating segmentation of hair into dark and light bands. A 15-year-old girl had segmented heterochromic scalp hair in association with iron-deficiency anemia. The clinical and laboratory investigations support the view that low serum iron levels play a critical role in reducing eumelanogenesis and in the possible failure of melanin transfer. The segmented heterochromic hair recovered completely after iron supplementation, which coincided with increased eumelanogenesis in the recovered hair. This clinical experience indicated participation of iron in the kinetics of melanogenesis within the follicular melanocytes.