Did your child have PICA?

My son who was born Dec 2008, is ALWAYS eating Hair and string/yarn( blankets fuzz). The first time i noticed it it was in his "diaper". never really thought anything of it, untill recently i have noticed that he does it all the time i have to actually watch him every second because he will eat the fuzz of his diaper, the carpet even the dogs hair, i found out what PICA is online and thought that maybe this is what he had, I am not sure if thats something i should call his DR about,, What do you think? Thanks