Here is a question I recently received about eosinophilic granulomas (known colloquially as rodent ulcers) in cats, and some resulting agression.
Hello Dr. Barchas,
My youngest cat, age three, has been treated for rodent ulcers since he was six months old. It's been a real struggle to treat it. He gets Depo-Medrol injections every few weeks, takes prednisone, on and off in between, and has just completed four months of cyclosporine.
I understand this can be difficult to treat, and I trust my vet implicitly, but I'm very concerned with Ozzy's behavior. Over the past several weeks he has become extremely aggressive toward me and the other cats to the point where if I look at him wrong, he goes into attack mode. He has always been so gentle and sweet, so I'm really concerned about this. When I suggested "roid rage" to my vet, she shrugged it off. I don't know what to do. I can't have Ozzy attacking the other three cats (and me) just because they're breathing. Can you suggest something? Feliway doesn't work; it only makes him angrier. Ozzy is on a food trial right now, but of course that does nothing for his personality. Thank you for your insight.
Angry cat by Shutterstock.
Eosinophilic granulomas are ulcers or sores that appear most frequently on the mouth or lips. Veterinarians often initially (and wrongly) believe that they are caused by injuries suffered during predation -- cat attacks rat, rat bites cat, and a so-called rodent ulcer develops.
It turns out that rodent ulcers have nothing to do with rodents and everything to do with the cat's immune system. Eosinophilc granulomas occur when the immune system becomes overactive and attacks the body. Autoimmune attacks tend to occur most frequently in areas known as "mucocutaneous junctions," where tissues change from skin to, say, buccal mucosa (also known as the inside of the mouth) -- hence, the lesions develop on the lips.
Like virtually every autoimmune disease, eosinophilic granulomas are devilishly frustrating to control. Two tactics generally are employed. First, immune system triggers should be avoided. The second tactic involves medications to attenuate the activity of the immune system.
The No. 1 immune system trigger in cats is flea saliva. Therefore, any cat suffering from the condition should be on a good flea preventative, and so should all of his housemates. In the olden days, a "good flea preventative" meant Advantage or Frontline. Many vets now believe a better product is a new oral preventative, Comfortis, that has recently been approved for cats. So, the first step is to get fleas out of the picture -- talk to your vet about Comfortis.
Some theorize that allergies to food and other things (pollen, mold spores, dust mites, cockroach feces, dog dander, and even human dander) might also play a role in causing eosinophilc granulomas. Therefore, switching to a hypoallergenic diet is a good idea. Sadly, it is harder to avoid stimulation of the immune system by allergies not associated with food -- although you could consult a specialist in veterinary dermatology and allergy about testing and possibly hyposensitization.
Owners of cats with eosinophilic granulomas should know that it could take several months to notice the effects of flea prevention or diet change.
Aggressive cat by Shutterstock.
The second tactic for treatment of eosinophilic granulomas -- medications -- is necessary in most cases. The mainstays are steroids such as prednisolone or Depo-Medrol. Prednisolone generally must be given regularly by the owner, whereas Depo-Medrol is a long-lasting shot, given at the vet. In my experience, many cats who don't do well on one of these steroids will do better on the other. Because Ozzy is not doing well on Depo-Medrol, consider talking to your vet about switching to oral or transdermal prednisolone. And make sure that Ozzy is taking presnisolone rather than prednisone -- in cats, the two medications are not as interchangeable as they are in dogs. Cyclosporine also is an immune system attenuator, and it can be used in combination with or as an alternative to steroids.
Behavior changes including aggression can occur as a side effect of steroids such as Depo-Medrol. However, the type of steroids that Ozzy is taking are different from the anabolic steroids that cause classic 'roid rage in people, so the analogy isn't perfect.
In my experience, cats with eosinophilic granulomas often become aggressive for a different reason: pain. Rodent ulcers evidently hurt like hell, and this can cause significant aggression in cats. I have known several extremely "fractious" cats whose temperaments changed dramatically when their eosinophilic granulomas were controlled.
So, with all of that in mind, here are my recommendations for Ozzy. First, use a good flea preventative on every pet in the house, and continue the hypoallergenic diet. Second, consider switching prednisolone for the Depo-Medrol (at a high dose, initially, then tapering once the ulcers are controlled). Continue the cyclosporine if possible -- it might help you reduce the quantity of steroids necessary to control the syndrome. Add a pain killer such as buprenorphine or tramadol into the mix. Finally, and perhaps most importantly, take precautions (including consulting a veterinary behaviorist if necessary) to ensure that no person or cat is injured while waiting for the new protocol to work.