The causes of yellowing hair are complex and varied. In addition to physiological factors such as western ethnicity, genetics, metabolic abnormalities, nutritional imbalances, tapeworm disease, psychological factors, ultraviolet radiation, perming and dyeing of hair can all cause it.
The exact cause should be determined in conjunction with family history, feeding history, symptom presentation and ancillary tests. The most common clinical causes of yellowing hair are inborn metabolic disorders and nutritional imbalances, especially in children.