Why does alopecia areata grow white hair?

Alopecia areata white hair, may be caused by hair follicle melanocyte lesions, may also be liver and kidney yin deficiency, malnutrition, local melanin deficiency caused. If there is alopecia areata, to go to the hospital as soon as possible to receive regular treatment. Usually can use some help hair black food, such as black beans, black sesame seeds, polygonum multiflorum and so on.