Suggest Treatment For White Patch With Hair Growth On It

My daughter was born with a chocolate brown birthmark, it is now pure white, with hairs growing out of it, its about 6cm long and 5cm in width, near enough a pure rectangle, it turns illuminist pink, no matter what factor she used up to 50, puts plasters on to it, or wears shorts the sun still seems to turn it raw pink. Any help appreciated.