About our hyper allergic Cat with Hyperthyroidism

Last Updated on: April 27, 2018

We’ve had our cat now for soon 14 years. A new medical condition with subsequent reactions and challenges had me, for the first time, sit down and write something about the experience. Hopefully this post will be of help to others. 

About 1 month ago from date, our feline male, soon 14 was diagnosed with Feline Hyperthyroidism. The symptoms had built up over time, with signs such as

  • weight loss
  • radically increased appetite
  • galloping metabolism, despite eating like a horse the cat did not put on weight
  • very high heartbeat frequency, even when calm
  • change of fur conditions, losses, change of textural feeling of the fur
  • frequently growling or rumbling sounds in gut or stomach
  • notice of significant or increase of thirst

if your cat shows any of the signs, and is elderly, make a vet appointment. Not later, make it sooner. Get blood tests done. We are still not sure what instigated or propelled our cat’s condition. Might have been genetic, might have been age, CAT-alyzed by diet. Why the latter will be revealed further down.

Did diet lead to Hyperthyroidism?

Well, we wonder about that. Last year the cat ended up badly injured due to a fight. And nearly lost his one eye. Thanks to formidable effort from specialists, and a quite expensive surgery, his eye was saved. But we had to keep him indoors for nearly 8 weeks.


From before our cat has been hyper allergic all his life. Pure luck and timing made it possible, with a at the time new vetrinary allergy test, to determine at least some of the proteins he did not tolerate. That taught us a lot about cat dermatology, and what most mainstream cat food is made of, why it is (generally) not good.

Different topic, fast forward

A blood sample substantiated his diagnose. Felimazole 2.5.mg twice daily was prescribed. According to the vet, 2.5mg twice daily is the norm when starting a treatment.

The first days we did not observe anything special. Then after a few days we noticed a psychological change, usually an hour or two after each pill. it developed into lethargy. loss of appetite, purring vanished, but also… heart rate went down, considerably.

We struggled with administering the pills, the cat hated them. Did a bit of research and discovered a liquid called Apelka Vet, 5mg/ml thiamazole. It actually had arrived in our country just a few days before. Guess we were among the very first to try it out. Same dose, i.e. 0.5ml/2.5mg.

First, from bad to worse

It could have been a connection between diet (we’d given him a quite a lot of fish due to metabolism/hunger) and the medicine. Not long after the transition, lesions or lumps started to break out, violently. you may notice it especially around ears, neck and shoulders. With it follow loss of hair, itching and frantic attempts to clean the area.

Cat lesions or lumps on retreat picture

Picture is taken while lumps and lesions are on the way down, thankfully. He scratched himself up quite a bit.

With 13 years of hyper allergic cat experience we’ve seen these symptoms before, many times. His reactions or outbreak could come as quickly as 15-20 minutes after he ate something he did not tolerate.

Those reactions however, were infused or driven by intolerance to proteins, and un-pure or highly mixed cat food. Based on experience I would generally advice against any supermarket cat food. Dry or wet, it’s more often than not a mix and mismatch of waste, a concoction of proteins not good for us or animals.

Years of feline dietary experience

Have taught us a bit. Our cat has been on (mainly) Royal Canin Hypoallergenic food for his entire life. Without this food, which is the purest/best there is (a new type is also out now called Royal Canin Anallergenic) his life would be rather miserable. He would have had poor life quality and frequent dermatological symptoms. Thanks to Royal Canin and also a bit of Hills low Allergen food we’ve managed to keep his condition in check.

Royal Canin food sensitivity products picture

our cat’s main diat, Royal Canin Hypoallergenic and now also the new Anallergenic dry food

Back to the topic, so where are we

The outbreak was substantial so the first thing we did was to eliminate high iodine intake (sadly meant no more [saltwater] cooked fish). He loves that but now, no more. Then we contacted the vet and brought him in for another blood sample.

This revealed values had dropped into the very lowest end of the spectrum. So he responded to the medicine.

A decision was made to reduce the dose to half, twice daily. He’s been on this dose now for approx 4-5 days. We still let him go out and he scratched himself quite a bit which have made things worse. A couple of days ago we therefore decided to detain him and put a collar (or lampshade) on. He will be kept indoors for some days while we monitor changes (hopefully progress).

We believe we see a change, lumps are drying up, he’s not so focused on the areas anymore. We’ve started to clean wash the areas twice a day carefully. He seems to like it, calms him down, the washing helps the drying up process and he’s less inclined to want to wash/mess things up. We’ve also noticed he’s not so itchy anymore.

This is about as far as we’ve come. Future will tell where things go from here. Hopefully this post will be useful to others in the same situation.

2 thoughts on “About our hyper allergic Cat with Hyperthyroidism

  1. First I’m so sorry about your cat having hyperthyroidism.
    Have you considered radiation iodine treatment?
    I would have done this for my cat, however he has now HCM
    There is no cure for feline HCM. Once the changes occur in the heart muscle, they cannot be reversed. Early treatment is aimed at helping the overly stiff ventricular wall muscles relax properly between heart beats and/or to slowing the heart beat to allow for better filling between contractions and for better blood flow to the heart muscle itself.

    He’s now 15 years one year after diagnosed.
    We just switched to a liquid form of medicine? He loves it, however I’m investigating changes in his behavior, which meds are changing his mood.

    Here’s what he is on at the moment:
    ❤️Heat medicine: once a day
    Clopidogrel 75 mg
    1/4 (for pieces broken) terrible taste
    Because clot formation is a worry when there is stagnant blood flow in the left atrium, cats with advanced HCM may need medications that inhibit blood clots. Low-dose aspirin is one basic choice, however newer clot-inhibiting drugs for humans, such as Plavix®, are starting to be used in cats. Exercise restriction may be recommended as well. Never give your cat aspirin or any other medication unless under strict instructions from your veterinarian.

    Lasix Furosemide 40mg 1/2 2 x daily
    To keep water out of lungs.

    Felimazole 1,25 mg hyperthyroidism
    2 x daily

    Apelka 5mg/ml
    Thiamazol/Thiamazum /Tiamazol
    Liquid form 2.5
    I’m not sure if he’s doing well on this…
    His mood has changed.
    Thinking it could be the wrong dose and works too fast… he’s so tried… grumpy

    I want him to have a good life, he doesn’t have long 3 months to 1 year is his life now due to the HCM.

    If he continues like this I will put him down. .

    Thanks for your information. I hope all the best for your cat.

    • Hi Cindy,

      thank you very much for your comments. Apelka turned out to be the big game and life saver for our cat.

      We were lucky, it was introduced as a fluid shortly after he started on his treatment. Pills are no fun to get into a cat’s mouth. Neither is it easy to make sure the pill is actually consumed.

      After some initial dosage and blood testing rounds he landed on 0.25ml twice a day, administered with a syringe. The medicine appears to taste ok, and he does not hesitate or protest at all.

      I’ve since learned that high metabolism and tendency to Hyperthyrioidism has become so common among cats that my vet said a study should be conducted. I think the culprits are hidden in the ordinary catfood and the processing used by manufacturers.

      It might actually be an advantage for our cat that he’s been hyperallergic all his life. And thus have lived on some of the purest catfood available.

      Sorry to learn about your cat, hope it all works out. It is hard when one runs into situations like that.

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