Breast?

Starr • Mother of a baby boy, married to his daddy.
I haven't got to talk to my doctor about it yet but I've noticed while changing that my nipples have what it looks to be white crust on them. I can pull the white stuff off and it's hard like crust but i don't recall leaking at all. Has anyone had this problem too and know what it is and what causes it? I'm 22 weeks pregnant.