Weird scabs on 1 1/2 yr old male rats back.

Question
I have two 1 1/2 yr old male rats that share a cage and I noticed a couple of months ago that they were both getting little scabs on their backs. I put this down to over grooming and sharp nails. I started to trim their nails and the problem has not gone away, but only changed slightly. Now one rat has big scabs all over his back while the other does not have any.
Is this mites or a food related problem, maybe it IS over grooming?

Thank you so much,
Garth

Answer
Hi Garth

It could be mites but if they are on a diet that is high in protein, this can also be the culprit.  Do they itch often?

You can apply some cortisone cream to the scabs and see if that helps, too.

Most rats groom alot and sometimes over groom. When they do this they often lose their fur in the areas they tend to groom most.

What does their diet consist of?