How Can White Patches In The Hair Be Treated?

My son has white patch in his hair so I took him to dramatologist 2006 he said that he loose some pig.. that's it. then 2010 I saw another patch took him to doctor again after listening all dramatolisge thought he might have some gene of Wardenburg syndrome. but talking to his Ontranylogist does not think that. so i stoped seaching. Now we noticed his left eye area getiing white patch. he is 16 what should I do