goose bumps on my mouse

Question
Dear Tamarah,

I got two fancy mice named Omie and Nombia about half a month ago, and Nombia has started to get hard goose bump like areas on his back. A few of them are scabbed over as if they have been bleeding. Any possible ideas of what it could be?
- Maya

Answer
Hi Maya,

There are several possible causes, and the best way to figure out the cause is to take the mice and their cage into a vet.  It could be pests like mites, an allergic reaction to something in the food or cage, parasites, or a host of other possibilities.  Without being able to see the mouse in person it can be hard to guess.  By any chance are both mice males?  Males are prone to serious fighting, so I would watch them closely and make sure the bumps and scabs aren't actually bites.  If you do see fighting or biting, no matter what the gender, they may need to be quickly separated.

If a vet isn't a possibility, you can try and get a photo of the bumps and write me a followup question, and we can try and figure it out.

Best of luck!
Tam