Steriod shot is killing my cat?

Keep force feeding him, so he has at least some nutrition.

What caused the paw to swell? It sounds like it may have been an infection.

If he doesn't eat on his own by tomorrow, call the vet and get him in again. Not eating is very serious.

Could you give us a few more details, such as the age of the cat, etc?

If he has lost that much weight in such a short time he isn't getting much in the way of calories if anything. The big concern is fatty liver disease. Overweight cats are at greater risk of developing it but thin ones can also develop it, I have a cat that was thin that developed it. There really isn't any trick to force feeding I never had very good luck with it. Petsmart has some larger syringes that are specific for force feeding. Do you have an emergency vet clinic in your area? That could be an option until tommorrow. He is probably also getting dehydrated and they could give him sub-q fluids. They might also help you out as far as forced feeding as well.

The trick I've found is to mix up some soft food and water to a slurry, put it into a large syringe (no needle), and squirt it in at the back corner of the mouth. After that, the cat will ususally swallow it. "Force" is somewhat misleading; if you try to force the cat to eat under any real pressure, it can cause real problems. Of course, there ARE cats that are fed with feeding tubes, but I hope that's not the situation you're looking at.

You can get fairly large syringes at Target, made for giving medicine to babies. Ask at the pharmacy. Those without a rubber gasket work best.

My cat that had liver disease was on a feeding tube for a few weeks. Of course I really hated that he was that sick but I thought feeding him with the tube was easier and less stressful for both him and me. It is still a time consuming process. I fed him four times a day until he started eating on his own and then weaned him off the feeding tube. It took about 20 minutes for each feeding.

catfreak64, PLEASE take my advice. Make an emergency appointment for your kitty first thing tomorrow morning - instead of the appointment you have for Friday - and have your kitty seen TOMORROW, no matter what. Have the vet who sees him do a complete CBC and chemistry profile. NO short cuts. The blood work must be complete, include everything labs normally test for. You need to find out if there is any organ damage or some other unusual problems. And you need to find that out without delay.

Also, PLEASE, in addition to this blood work, have a fPLI test done right away, at the same time. You need to rule out pancreatitis when a cat is not eating. And that's the only reliable test your vet can go by.

Steroids CAN make a cat stop eating. Any amount of this medication, in any form, oral or injected. Why, I have no idea. It's not a side effect or adverse effect listed anywhere. Yet, I have one cat who is totally intolerant to steroids.

Anyway, you need to find out what's going on with your kitty, whether there is any organ damage or pancreatitis involved. And you need to have a good vet who will work with you.

Listed as secondary disorders steroids can cause pancreatitis, hepatic lipidosis, etc.
(This reminds me of pancreatitis that can be a sudden and unexpected adverse effect of vaccination.) I'm urging you to test for it right away. Any liver related problem would most likely show up in the results of the chemistry profile.

I completely agree.

I'm also wondering why it's assumed it's allergies when there was an infection? Did he complete a round of antibiotics? Why does the vet think it's not a reinfection?

I'd follow Violet's advice and get a full work up of the kitty tomorrow. This could be serious. 4 days without eating and such drastic weight loss is not good. In order to fix it you have to find out exactly what it is.

One of my cats get regular steroid shots and it definitely affects his eating. He won't stop eating all together though but will only eat a quarter of what he should on his own, if even that. I have to force feed him for about a week. Fortunately he's a very easy cat and I can feed him by putting the food in his mouth and sticking it to the roof of his mouth. Most cats would fight tooth and nail against it though.
Is the cat drinking? If so that's a good thing. If not it's even more important to get him in asap. Waiting until Friday is not an option. He has to be seen tomorrow.

As far as force feeding goes I would recommend getting a good quality, high protein canned food that is soft as well as some kitten formula. The kind that comes in a can is easier to use than the powder and cats tend to like it better. If your cat will drink he may even lap some up which would be great.
Mix the canned food with the kitten formula to make a gruel. Put it in a 10ml syringe with a large opening (can be found at pharmacies and some pet stores). Wrap kitty tightly in a towel like a cocoon so that he can't move. You can also buy a cat restraining bag which is a little easier to use. Then inject a little food at a time in the corner of the mouth. You should do this several times a day.
I'd also recommend getting some Nutrical or similar generic and give him a full ration of that per day. It gives him some extra calories and nutrition. You can either try to put it on a finger and stick it on the roof of his mouth or you can use a 3 or 5ml/cc syringe to inject it which you can get at the pharmacy counter at most pharmacies or from a vet office. Nutrical is very thick so you can't draw it up into a syringe so you have to put it in the other way. Pull the plunger out and squeeze some Nutrical into the syringe and put the plunger back. Make sure to rinse it right after or it will dry and the plunger will get stuck and you can't use the syringe again.

If the vet thinks that your cat needs sub-q fluids more than once ask if he can teach you how and send you home with the things needed. It will save you money from having to go back and get it done at the vet and it will be less stressful for your cat. It's really easy to give sub-q fluids.

Hopefully this is just a reaction to the steroids and will go away soon. Things like this is a good reason why it's better to give oral steroids to an animal that has never had it before instead of giving a shot that will last for several weeks. If there is a bad reaction to the meds you can stop the oral ones but there is nothing you can do if you've given a long lasting shot. It's a good lesson for anyone else whose cat will need steroids in the future. If the vet suggests it ask for liquid prednisone instead of giving the shot if the cat has never had it before.

My kitty Maia had a cortisone shot 2 weeks ago for what my vet thought was a stress/skin allergy disorder. She also lost her appetite for a few days and I was worried because this girl is always in the kitchen before me!
I'm sorry your guy is having such a bad reaction, if possible I would take him to a different vet. I don't know if I agree with giving a steroid shot for a swollen paw that was previously infected.....there could be much more to this then allergies.....
to his quick recovery