White hair refers to the complete or partial whitening of hair, which can be divided into congenital and acquired types. Congenital white hair often has a family history, and localized white hair is more common, mostly seen at the front hairline. Acquired white hair includes senile white hair and juvenile white hair. Some elderly and weak people have very few white hairs. Juvenile white hair occurs in children and adolescents, and often has a family history. Except for the increase of white hair, it does not affect physical health. Sudden occurrence of white hair in adolescence is sometimes related to nutritional disorders. Mental factors can affect the whitening of hair. White hair can be a symptom of certain diseases, such as progeria, vitiligo, etc.