Overgrooming months after thyroid meds stopped

[angela638x]

Hi. Lola has CKD and mild hyperthyroidism. She was eating dry Hills k/d and weruva wet food. In July she was trialed on Methimazole for several weeks until she began to vomit and scratch/groom excessively. She began to lick all the fur off her belly. The vet stopped the med entirely as it was clear she was allergic. The vomiting stopped, woo!

The fur never came back and Lola kept grooming her belly. She bites at her belly and licks a lot- a scab is forming in one area. She also began scooting. Her poop has always been normal.

The vet now wonders if she has a food allergy and switched her to Royal Canin renal dry, but the first night I gave her just a bit of it mixed with her other food, she vomited soon after eating.

I am wondering what to make of all this. Is this environmental allergies? I am not sure how to proceed.

 

[FeebysOwner]

Hi. It is possible that Lola got a too large of a dose of methimazole, as opposed to being allergic to it. What was her T4 level and how much methimazole was she getting? Was her level rechecked after she had been on it for a while?

Over grooming can also be symptom of hyperthyroidism in some cats. But itchiness can be related to CKD as well. Butt-scooting can be associated with constipation, which could mean she is a bit dehydrated - and, both of those can also be common in CKD cats. Of course, she should also have her anal glands checked, just in case, as that is also a common issue when you see butt-scooting.

I can't imagine that the vet hasn't re-checked her thyroid and CKD levels just to see where they are now, but if they haven't I would get that done first. If that has not been done, I would forgo concluding she has some sort of allergy, just yet.

While it is true that cats can become allergic to most anything, at anytime, regardless of their previous exposure, it is one tough endeavor to try to resolve. I'd rule out any possibilities that it is associated with her hyperthyroidism or CKD before going down that path. Btw, I wouldn't consider her eating a small amount of a new food as the definitive cause of her vomiting, so not sure it seems applicable to try to change her food at this point.

 

[angela638x]

She’s consistently been doing ok re: her CKD. When her labs were done in July when she began the methimazole, they found her T4 was then too low. That, plus her symptoms, prompted the vet to stop the med.

I mixed the new food in and she vomited moments later, then turned her nose up to the rest of the dry food. She ate wet food just fine.

I will note that Hills k/d changed their formula? She never stopped eating it but I don’t know if that’s relevant and I did bring it up to the vet. But she’s has no GI symptoms. She’s just so itchy!

 

[FeebysOwner]

A too low reading of her T4 likely just means the dose was way too high for what she needs. It is fairly customary to stop the med at that point, wait a while, re-test the T-4 and see where it is at. Then, restart the med at a lower dosage. For whatever reason, vets tend to want to start with 5mg, either once or twice a day, which is usually too high. My cat had a T4 reading of 4.5ug/dL and the vet wanted that higher dose. I had read enough to know to start lower, so we agreed to give her 1.25mg twice a day - that was enough to bring her T4 down to where it needed to be. A cat with CKD should have a T4 value between 2-3. The reason for this is that bringing the T4 down too low can negatively impact kidney function. But, having the T4 stay too high can cause misleading readings on how well/poorly the kidney function is.

Hill's k/d, as is true for other Hill's products, went through a packaging change, as well as what they call 'aesthetic' changes to the size, shape, and taste. They did allude to some formula changes as well, but to find out exactly what was changed would require reaching out to Hill's and asking what the changes were, specifically with regard to the k/d version.

I wonder if your vet would be willing to prescribe an antihistamine as a test (e.g.; Benadryl, etc). It works the same way it does on humans with allergies to help reduce the itchiness. It won't solve the cause of any allergy, but it would at least give her some relief if it worked.