A birthmark in hair white, also known as poliosis circumscripta, is a condition where a patch of hair grows in white or gray. It is a type of localized albinism that affects only a small area of the scalp.
Birthmarks in hair white can be caused by a number of factors, including genetics, autoimmune disorders, and certain medical conditions. While they are generally harmless, they can be a cosmetic concern for some people.