My cat has a lump after vaccine. Is it necrosis or just healing?

Great question! This lump could be a localized reaction to the vaccine if the lump is in the area where the vaccine was given. Other options could be a cyst or a benign tumor. Given it's not painful and if she is otherwise acting normally, this isn't an emergency. Keep an eye on this lump, and if it doesn't go down over the next couple of days or gets bigger, then I would have Poppy seen by a vet. Good luck, I hope this helps!

It does not look like post-injection reaction. I would rather suspect an insect bite, reaction to a tick, cat bite (if Ori goes out at all) or self-inflicted small wound from scratching the area. Please, keep an eye on it, small skin wounds often heal rapidly without treatment. If there is any discharge from the wound you can use 4% chlorhexidine skin solution to clean it. If it gets bigger or starts bothering Ori, take her to your local vets for a check.

Poor girl. Due to her age a mass here would be less likely as the cause for this hard lump. This may be an abscess or even a cyst. It is difficult to tell without feeling it in person, however, if it does not go down on its own within a few days to a week, then I would recommend having your vet check it out further. If it is an abscess, then cats typically will start to act ill (decreased appetite, low grade fever, lethargy) after a few days, in which case the abscess would need to be drained by your vet and then KitKat would need a short course of antibiotics to get things to heal well. Otherwise, I would recommend monitoring this for now to see what happens. I hope that Kit Kat's strange lump heals well soon! : ) Best wishes and take care.

It does need to be noted with your vet to verify if it is a vaccine reaction. Cats can have injection induced sarcomas which are cancer and require surgery. The general rule is if it is there longer than 3 months or gets larger, then surgery is warranted, otherwise they go away on their own I would have them document the vaccine site and the size for proper monitoring in the future.

Poor Munchkin! I'm sorry to hear that he's having this problem. Without being able to examine him, or at least see a photo of the area, it's hard to say what this might be and whether it is healing appropriately or not. From your description, it sounds like it could be a ruptured cyst or skin tumor of some kind, or possibly a rather nasty localized infection. It sounds like you have been doing a good job of keeping the area clean. I wouldn't consider this problem to be urgent as long as he is acting normal otherwise, but I would recommend taking Munchkin to your regular vet tomorrow to have this checked. He/she can examine the area to determine if additional treatment is needed, to make sure that it heals without further problems.

Hi, sorry to hear Keanu is having problem. This very well could be a type of vaccine reaction. I would monitor the site to see if it gets better or if a lump appears. If a lump appears, he should be taken back to the vet as this is serious. It could be an infection also, which may resolve on it's own or may need antibiotics. I hope he gets better!

Hi there, and thanks for your question on Petco Pet Education Center, formerly Petcoach. It looks like Sophia is likely developing an abscess, which is a focal internal infection - the timing makes sense if she was in a fight 3 days ago.. If so, a topical product such as Neosporin won't help - she would need systemic antibiotics, either given orally or as an injection. I recommend having her seen by your vet so she gets the appropriate treatment. In the meantime, keep the area clean by gently washing it twice daily with soapy water. You can use a gentle dish soap such as Dawn. Hope this helps.