Heterochromia of the hair could be from the lighter colored hair being thinner than the darker color. When different colors of hair is symmetric (ex. red beard with blond hair) heterochromia is physiologic. But when
distribution of the hair is two colors on the same scalp, it reflects pigmentation disorder and can be from genetics. It could also be from heterochromic scalp hair in association with iron-deficiency anemia.
There was a very famous case of heterochromia iridum where an 11 year old Chinese boy got this and the result was a heterochromia, (As shown in picture below) his roots being light brown and the rest of his hair being black, and the light colored hair being thinner.
distribution of the hair is two colors on the same scalp, it reflects pigmentation disorder and can be from genetics. It could also be from heterochromic scalp hair in association with iron-deficiency anemia.
There was a very famous case of heterochromia iridum where an 11 year old Chinese boy got this and the result was a heterochromia, (As shown in picture below) his roots being light brown and the rest of his hair being black, and the light colored hair being thinner.