American Fancy Rat & Mouse Association

This article is from the Spring 2001 AFRMA Rat & Mouse Tales news-magazine.


Hairless Rat With A Rash

An Christensen, e-mail
Q I’m having a problem that I hope you can give me some assistance with. I have a hairless rat who a week ago developed a rash on the lower portion of her body. It covered her hindquarters and about an inch from the base of her tail. The rash dried up slowly over a period of about a day and a half but left some dry flaking behind. I had experienced this rash before with her, but it cleared up within 1–2 days during which time her appetite and personality remained the same. About a day after the most recent rash started looking noticeably better, my rat started acting listless and lethargic. Her appetite is still okay, but she has lost a little condition. I have supplemented her regular diet with several (healthy) foods that I know she’ll eat, and so far her hydration and condition remain okay. I don’t know whether the rash and the illness are connected, but it seems rather coincidental. I am a veterinary technician at an animal clinic that deals with small animals (dogs and cats primarily).

One of our veterinarians does handle exotics (birds, rodents, reptiles, etc.) but he is out of town for another week. I have consulted with one of our other vets, but she has a very limited knowledge of rodents. As far as treatment goes, I am medicating her with .30 ml of trimethoprim Sulfa twice daily and have been doing so for 3 days now. She does seem a little better, but the improvement is slight, and I’m concerned that we may lose her if she doesn’t snap out of this soon. I have noticed that a new rash seems to have developed, this one on the upper half of her body, mainly on the ventral side. The rash does not seem to bother her as she doesn’t scratch or itch at all. I keep my rats on cob, and just cleaned her cage before all this began. The bedding I used is from a bag that I had already opened and made many cage changes with. I will take her into our clinic tomorrow to see if any headway can be made. I also plan to change her bedding to a clean aspen or a lizard type bedding in case the bedding is to blame. So far, the answer that we have come up with is that her immune system has been compromised either by this rash, or before, allowing the rash and subsequently this lethargy and ‘cold’. She also does have a bit of clear discharge from her eyes. Her stool so far has been normal. I haven’t introduced any new rats or any new animals into our house, and I haven’t handled any other rats or rodents at work recently. I apologize for the length of this mail, but I wanted to include as much information as possible for you. Hopefully, she will be improved by the time you are able to reply, but any ideas you can pass along would be greatly appreciated. I will be poring over all of my issues of AFRMA Rat & Mouse Tales and all of my other information in search of some answers. I thank you in advance for any help you can give me.

Answer from Karen Robbins

Jiggly Puff
This Hairless Dumbo, “DRP Jiggly Puff” owned by Jane Gorden, shows off her smooth skin and lack of hair.

A I would look at the bedding as a possible problem. I know corncob can mold very quickly when it gets wet. One time I saw a Hairless rat with a dry, flaky skin, and it was housed on CareFRESH™. We don’t know if this was the problem, but the owner had just put the rat on CareFRESH™ when it had previously been on Sani-Chips. She then changed back to Sani-Chips and said it cleared up. The aspen may help or try paper towels/towels for a few days to see if there is any difference. Are you putting any kind of ointment on the rash? The Hairless rats here that I’ve known don’t seem to really have much of a skin problem. A couple of times male Hairless have developed a yellow, grungy skin that would have been the same for a male haired rat to have (an extra oily coat where they get the yellow, dirty coat and yellow/orange gunk on the skin). Bathing usually takes care of this problem. With your rat I would get a vet to check for any kind of fungus or bacteria and try some tests to find out what is the problem especially since she has runny eyes and is not acting herself.

Answer from Carmen Jane Booth, D.V.M.
A I do not have all my books unpacked so I cannot give you as much information on the different genetic strains of “Hairless” rats as I would like to. In general, rodents that are classified as “Hairless” are immune compromised or immune deficient. These animals are more susceptible to disease than their furry counterparts. In conventional caging situations such as what one would have in a home situation, these rodents do not usually survive long or even up to a year. The rash in this rat is probably caused by a bacterial infection. My suggestion would be to have the owner ask the veterinarian to prescribe Baytril at a dose of 10–25 mg/kg for this rat. This a higher dose range because of the compromised immune system. No matter what the exact cause, this rat will probably need to be on antibiotics for the remainder of its life. In general, people who try to house “Hairless” rodents under conventional (in their home) environmental conditions, need to be aware that these rodents do not survive well and have shortened lives because they are not able to fight off infections as their furry counterparts can. *

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Updated February 13, 2015