Some other skin diseases could behave like this. They have had mites for over 4 months now, and I am just going crazy trying to get rid of them. I have disinfected their cages, given them baths an changed their litter several times. On the advice of a friend who had rats, I even tried to shave their back area where the mites had laid eggs. I have been trying to give them baths every week, and use the spray for birds to control the mites.
Nothing seems to work.
I thought i would give this a try and see if you had any suggestions. Most mites are species specific, so generally the mites of rats will not affect other animals or man. Mites in rat colonies may best be controlled, but are difficult to eliminate. You should look at the offending creatrures under a microscope to be sure of what you are dealing with. Some mites may survive for some hours in bedding and other material in the colony, so the treated rats should be placed in clean surroundings.