142 Segmented heterochromia in scalp hair.

Kyeong Han Yoon1, Daehwan Kim1, Sungbin Im1, Seong Hyang Shon2, Won Soo Lee3. Department of Dermatology1 and Laboratory2, Ajou University School of Medicine, Suwon, Korea, and the Department of Dermatology, Wonju University Medical College, Wonju, Korea3

Segmented heterochromia of scalp hair is a pigmentary disorder of hair characterized by alternating dark and light segments on each hair shaft. It is known to be associated with iron deficiency anemia, but little is known about its pathogenesis. A 11-year-old boy who had black scalp hairs presented scalp hairs showing alternating dark and light segments on their shafts confined to his vertex for about 1 year. He had had iron deficiency anemia for 6 years. There was no remarkable family history of illness. On examination black hairs and hairs with alternating segments were intermingled on the vertex. There was no difference of thickness, length, or straightness between the both groups of hairs. His hemoglobin was 9.1g/dl; hematocrit, 28.9%; mean corpuscular volume, 60.7fl; mean corpuscular hemoglobin, 19.2pg; mean corpuscular hemoglobin concentration, 31.6g/dl; serum ferritin, 2 g/l; serum iron, 11g/dl; and, total iron binding capacity, 561g/dl. His liver function tests and urinalysis were normal. Under light microscope, dark segments of the hairs were densely packed with black pigmented granules while black or brown pigmented granules were loosely arranged in light segments. Fontana-Masson and GP-100 stain revealed no difference in the number of melanocytes and melanin pigments between normal and pathologic hair follicles in biopsy specimens of scalp. In transmission electron microscopy, the amount of cortical melanosomes was getting decreased along the hair shaft from the dark segment to the light segment. In dark segments, dense ellipsoidal melanosomes were noted while loosely packed round melanosomes were found in the light segments. There is little significant findings related with the pathogenesis of segmented heterochromia, we suggest a possibility that eumelanosomes can be replaced by pheomelanosomes or there may be a transient retardation of melanogenesis in human melanocytes under certain conditions.