My rat is covered in scabs, how do i get rid of them?

i think they were caused by too much protein. i used to feed my rats loads of nuts (i dont anymore) they eat a load of bran flakes and rice krispies, so im not sure if thats causing his scabs. they are all down his left side, under his chin and some on his back. i havent seen him scratching too much, but i think he is making them worse by scratching them. like when they heal i ume they get itchy so he scratches at them which makes them bleed or he ends up with more.