little sores on my pet rats back

Question
QUESTION: My 2 year old female rat has a lot of little sores on her back, they scab over, but never seem to go away. I don't think she has mites though becuase i have another female rat in with her and she does not have any little sores. Also she seems to not be moving around as much, and barely ever comes out of her little house. I thought that maybe my other rat was doing this to her, they are sisters and came from the same litter, but i'm not for sure if my other rat is doing it to her or if she has an illness, I've seperated them into different cages but i don't want to keep thme away from eachother if it's not the other rats fault, but if it is her fault i don't want to put her back in there to have my other rat kill her. Could you please help me, any suggestions would help, i don't want her to die. I've looked at other people's answers who say they have little sores on their rats back and the answers always say mites. Is it possible that one of my rats could have mites, while the other doesn't? I think it's soemthing different than that. Thank you very much

ANSWER: Hi Emily


Do your rats fight? If not, put them together. I doubt that is what is happening.  Sometimes rats have sensitive skin and have problems with their diet that causes scabs. Can you tell me what her diet is for starters? Before I continue, I need to know what she eats.  Please write back with a follow up and we can continue from there.

Sandra

---------- FOLLOW-UP ----------

QUESTION: I've never seen them fight really, only like when they play wrestle, i put them back together though. She eats food called "Living World Extrusion" its like little block of food, its supposed to have everything they need. Her bedding is the Carefresh stuff. thank-you very much for writing back, i hope this helps you, if you need any other information ask, I'll just write back.

Answer
Hi Emily

I am not familiar with this brand of food but I will tell you that rats  should not exceed more than 15 to 18 percent protein in their diet. If they do, it can eventually cause problems with kidneys in the elderly rat, and when they are younger, it can cause allergies that take the form of skin problems.  Check the back of the package and see how much protein is in the rats  diet.   
About mites: mites usually go from one rat to another and  they are species specific.  Mites do not live on the rats body, instead, they live in the bedding or in wooden toys or in  cracks and crevices. If there are mites,they very well could bite your rat, cause irritation and leave the rats body and you don't notice them on the rat. Something tells me though that this may not be the case. I am leaning more toward a protein sensitivity or skin allergy or else a case of dermatitis.

Here is something you can try if you want. At the store you can find hydrocortisone cream and neosporin ointment. You can use these on the scabs to see if they heal as well. It can be irritation. Rub in the medications well and they wont hurt the rat if she licks it off but try to keep her busy for a   bit so it absorbs . Use one a few hours before using the other, don't mix them.
Again, though, if you don't mind, turn the package over to the food your using and check the protein content...if it falls within the acceptable range (15 to 18 percent) its fine but if its over 20 percent, this could be the cause of the dermatitis.