Mouse ear tip suddenly missing

Question
I have a year old fancy mouse who is caged alone.  There is nothing sharp in his cage from what I can tell. Tonight I went to give him his nightly treat and noticed a small chunk from the tip of his ear was missing.  There was some dry blood and scabbing. After reading to check for hair loss I checked him thoroughly and there may be some mild hair loss on the back of his neck. He is not scratching. He is eating normally. He is exercising on his wheel as I type this. I just don't know if I should freak out or if I should see if it is contained.

Answer
Hi Lynsay,

First, you don't need to freak out!  Ears have great bloodflow and typically heal very quickly.  He may have caught his ear while scratching or pinched it in something, so you did great by checking the cage over carefully for hazards.  Also take a peek around the cage - do you have any other animals or hazards near the cage that could have caught his little ear?

I am not sure how much of the ear is missing, so it's tough for me to tell you if this was an accidental injury, or mites or allergies (which I am guessing is why you were looking for hair loss).  Both mites and allergies would cause an excess of scratching - is he itchy all the time?  Scratching at his face and shoulders all the time now?  Are the spots where he appears to be losing some hair also scabby, red, and irritated?  If there are no scabs in these areas and no actual bald spots, it is normal and okay for there to be less dense hair on the back of the neck than on the shoulders.  Let me know how these areas look in a followup, and a picture of the ear and/or spots with hair loss and I can help more thoroughly.

If he isn't scratching all the time or scabbing anywhere else, then it sounds like just an injury.  If he'll let you (without getting anything in his eyes/on his face), you can clean the ear each day to prevent it from getting infected while it heals.  Get some betadine (a safe iodine solution) and pour a few drops into a small cup of warm water until it turns the color of tea, dip a folded tissue into the solution and dab the ear with it.  It's okay if it stains.  You don't need to rub, pinch the ear, remove any scabs, or soak it - just dab gently to get a little of the betadine on the ear.  You can then dry the ear off with another clean tissue and apply a tiny amount of triple antibiotic ointment with clean fingers.  You only need a teeny amount.  He'll probably clean it off anyways, but in the meantime, it will keep debris from getting into the injury.  You can do this once a day if he will let you.  If he isn't having it, that is okay, too, just keep his cage as clean as you can manage and let me or your veterinarian know if it gets worse instead of better.

Best of luck, and let me know how it goes!
-Tam