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My cat's jaw is swollen. Could it be an allergic reaction to dewormer?

Updated on September 23rd, 2025

Pet's info: Cat | Mixed Breed | Male | neutered | 3 years and 9 months old

My male cat Lucky came in late. His lower jaw is swollen. He’s actually sleeping now, I’m a wreck. I administered Pet Armor deworming pills to all my cats; could he be allergic or too much piperazine? Didn’t see bite marks; I do live in forest. If not better by morning, I’ll take him to vet. Really swollen!

2 Answers

Most Helpful Answer

Published on May 23rd, 2019

This does not look like an allergic reaction which could come from a systemic medication. This lump/growth should be ideally examined by your veterinarian to have a definitive diagnosis. Your vet will examine it and possibly perform with an FNA (fine needle aspiration) or a biopsy.
Differentials would include skin cyst, an insect bite, the result of a trauma, infections or benign or malignant type of tumors (very unlikely given the age).
Hope this answer was helpful, but please do not hesitate to contact us again on the forum or by requesting a consultation if you have any more questions or to discuss it any further. If this answer was helpful please let us know, this will be used to improve our service!
Vote Icon3Pet Parents found this answer helpful

Related Answers from Veterinarians

  • Answered By Dr. Strydom, DVM

    Veterinarian

    Published on May 27th, 2017

    Hello. Sorry that Patches is having this issue.

    I would say this looks serious. I don't want to upset you or scare you but cats tend to get a lot of oral cancers and I think this resembles something along those lines. They also get something called eosinophilic granuloma complex. It could be that. I sincerely doubt this is a bite of any kind. It is better to be safe than sorry and have it checked out. It is really hard for me to tell based on a photo. I suggest you take her to your vet for an exam and that way you will know.

    You have to be careful with cats and home remedies. They are very sensitive to medications and cannot take a lot of things that humans and dogs can. I would definitely not try to treat her with anything at home especially since we don't know what we are dealing with.

    I hope this helps. Best wishes.

    Dr. Amber

    Vote Icon

    1Pet Parents found this answer helpful

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