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Pet Rats/Bulging eye and hair loss


Rat with bulging eye
Rat with bulging eye  

Hair loss
Hair loss  

I have three female Russian Blue Dumbos that are about 10 months old. I have two queries I am hoping you may be able to help with. I have not been able to find answers elsewhere.

First - Bulging eye
One of my rats had one eye noticeably smaller/flatter than the other when I got her at about two months old. I asked the breeder and was told she was expressing genes for two different sized eyes and there was nothing to worry about. She has always had a slight head tilt and has always been much smaller and a bit clumsy compared to the other two. The small eye has gradually started bulging over the last 8 months and is now much larger than the normal eye. There is no discharge or visible swelling around the eye. She is eating, drinking and playing as usual and it does not appear to bother her. I took her to a vet recently but they weren't able to suggest anything other than 'perhaps she has a tumour growing behind the eyeball'. I have attached some photos from different angles and a photo of the eye when she was a youngster. Have you seen anything like this before? How worried should I be? She is an absolutely lovely rat and I don't want her suffering in any way.

Second - Hair loss
All my rats are losing hair over their lower backs. The hair in this area turns copper in colour and then falls out. The skin underneath is clear and there are no scabs or wounds. They do not scratch excessively and there is no visible evidence of mites/fleas. From googling, it sounds like too much protein can cause hair loss. But also too little. And too little copper. As all three are affected I was thinking diet might be the likely cause. They are fed a mix of two pet shop rat foods and a feed I make myself (using information from 'The Scuttling Gourmet' book). They have fresh fruit/veg every day and vitamins (Dailyrat3 mixed in with food and occasional bottles of water containing Dr Squiggles - Daily Essentials 1). I removed all the additional vitamins for a week and the hair loss got worse. But I am struggling to determine the cause. My previous male rats were fed pet shop rat food and did not have any hair loss. I have attached a photo so you can see the colour change. The hair loss is more severe than it appears in the photo but my rats are wigglers and wouldn't hold still. Do you have any ideas on what might be causing the hair loss?

Thank you very much for any help you can provide.

Based on my experience and extensive research of rat breeders, my first instinct tells me that the breeder you adopted your girls from is a careless or poor quality breeder.  Of course I may be wrong, but I am basing my thoughts on what you are telling me is happening with your rats.

The information I'm going to give you is based on my knowledge as well as advice I sought out for you from friends or mine who are rat "experts".

First I'll address the eye bulge.  This could be any number of things from a genetic defect (thus my thoughts about your breeder not selectively breeding for health) to something more serious.  Because you said that her one eye was visibly smaller & flatter from babyhood and has been increasingly bulging over 8 months, I tend to think it may be a genetic flaw.  Even if this is the case, it might still become something serious if it continues to bulge more and more.  It may begin to cause her pain, cause blindness, or could rupture.  It is possible that the eye may have to be surgically removed.

Another thought I had is a possible pituitary tumor (PT), a neurological condition which causes the pituitary gland to grow abnormally and push up against the eye causing bulging (the tumor generally is on one side, thus causing one eye to bulge and not both).  Another classic symptom of a PT is head tilt, although head tilt could also be a genetic defect.  Other classic symptoms of a PT are loss of coordination, clumsiness, and loss of use of limbs (starting with the front limbs and difficulty holding food).  You didn't mention this last symptom.  However, the symptoms of a PT usually come on rather quickly, one after the other, starting with coordination issues, then eye bulge, loss of limb use, and finally loss of the ability to chew and even lick...all within a few weeks or a month.  There is no cure for a PT but there is prescription medication that can reduce the swelling against the brain that can alleviate some of the symptoms and possibly extend a rat's life.  But because you said the eye has been bulging for many months now lessens my thoughts that it is a PT, but it is still a possibility to consider.  Here is a link to more information on PT:

There are a number of other medical conditions that can cause the eye to bulge.  Is there any smell near her eye? If so, it could be an abscess.  It could also be a tumor (non-PT) growing behind her eye, or possibly even glaucoma:

I would highly recommend that you take her to an exotic vet who has extensive experience with rats.  I have access to a database of exotic vets and can help you find one in your area if you provide me with the city (or nearest large city) and state you live in.  The vet would likely prescribe penetrating antibiotics and possibly a steroid like Metacam to reduce swelling and help with pain, since this may be uncomfortable for her.  

Now to address the fur color change and fur loss.  I had a Russian blue rat as well.  I adopted mine from a breeder who I later found out was a fly-by-night "careless" breeder.  My blue girl started to get a tint of brown fur along her back when she was only 6 months old...not a good genetic species of a blue.  A good quality Russian blue should remain a rich blue for most of her life.  However, blue rats do "rust" as they age, but yours are way too young for that.  Thus again, my thoughts about your breeder that I mentioned above.  I would not be as concerned about the color change (it is likely genetics) as I would be about the fur loss.

Fur loss could be any of several things.  One possibility may also be related to poor your girls have rex or hairless in the background?  (it could be a recessive gene).
Assuming you take your one girl to an exotic vet for her eye, have the vet check for mites, as mites are hard to diagnose sometimes if it's mild.

Another possibility, which was your thought as well, is that the hair loss could be diet related.  I doubt this is a food allergy however, as there isn't any inflammation, rash and the location is not usually where you see hair loss with a food allergy.  To rule diet out, you would need to do an exclusion diet.  In the US, it would mean to offer only lab blocks.  I am not sure if that is an option in the UK.  You would then slowly add different elements back in to the diet, carefully observing any changes in the fur loss.   

I hope I have given you some good information about some of the possibilities, however I strongly advise a visit to an exotic vet, especially regarding the eye bulge of your one girl, as this could be something quite serious.  Again, I will be happy to find you an exotic vet if you reply with your location.  I hope to hear from you soon.

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Irene Murphy


I can answer a variety of questions regarding adoption and care of pet rats throughout their lifetimes, including questions about their health and well being, temperment, diet, bedding, cages, toys, etc. I will try to answer your questions to the best of my ability in a timely manner and I have an abundant amount of resources to help me to help you with your pet rats. I love rattie pictures, so include pics with your question if you can. You may ask me medical questions, but please be advised that I am not a vet. I may use my resources to answer some medical questions, however, I will need to refer you to your local vet with medical questions that I feel I am not qualified to address.


I have been a huge rat enthusiast for many years. Since becoming a rat owner, I have educated myself in all areas of pet rats from every resource I could find including the internet, books, conversations with local exotic vets, as well as several local rat breeders.

I have a college degree but not in the area of animals. I have obtained my extensive experience and knowlege of pet rats all on my own because in my eyes, pet rats are the most interesting and fascinating creatures you can ever imagine to have as pets. I also am saddened by how mislabeled and misunderstood these amazing and extremely smart animals are by the majority, and my mission in life has become to educate and change as many people's perceptions of rats as I possibly can.

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