Eosinophillic Granuloma Complex

Anybody? Help me!
have 3 cats, all with a good number of health issues. IBS, Urinary Tract Disease, allergies, my youngest was "diagnosed" or assumed to have Eosinophillic Granuloma Complex.
They currently eat an all raw diet, I am lucky enough to have a pet food deli near my home.
The skin issues of the eosinophillic granuloma complex ( my vet explained it to me as an auto immune disease where allergies appear as skin lesions, they get bad, she licks, they can't heal, she gets out of every cone, body suit, rigged contraptions known to man, and has to go on high dose steroids which I HATE) are persistent and very hard to keep under control. Would it be better to feed her a prescription diet? But for skin issues or for allergies? I don't know what she's allergic to. We have eliminated EVERY typical from the home, her food contains nothing but single source human grade animal protein, organs and bones. All poultry is a no go, so far the only thing that seems to be okay is rabbit and or venison but she still gets her sores pretty persistently and always the same 2 spots.

I have had a few cats with EGC and, yes, all were due to a protein allergy EXCEPT one that was due to a flea allergy. Literally one single flea bite caused a massive EGC that just wouldn't heal. We went as far to do a biopsy to make sure it wasn't something else.

What finally worked for her was using Quadratop Ointment, applying gauze over the sore and then wrapping her neck with vet/sports wrap (the sore was pretty high up on her neck...just about where the e-collar sits) and then placing a plastic e-collar over that.

It took a good 8 weeks to get the neck healing. She had 2 recurrences and then, finally after 16 weeks she was good as new.

We also used an oral antibiotic for her to help with secondary infection. We also used CapStar every 3rd day with her until the wound was healed enough to put a topical flea medication on her.

I will note that she was seen by several vets and flea combed multiple times and no one could find fleas on her. But, we didn't finally link it to a flea allergy.

Did you do allergy testing? How much does that cost? I have to figure out what it is, this is just awful. Her worst one is on her thigh, there is NO WAY to wrap it!! I've tried everything.

I know you're a raw feeder and I have zero qualifications but I do have an allergy ridden cat who has had a couple of hot spots that we're not sure weren't ECG. I have read (and it's rare but happens) of kitties who simply seem to react to all proteins, no matter what they are. An elimination diet may be helpful. You could do it raw, stick to a single protein source, nothing else added for 12 full weeks (I notice you said you're using 2, it's possible she's reacting to one of them) or if you're willing to go that direction one of the hydrolyzed vet diets that's on the market might help. I have mine on one and while I hate the ingredients I'm hopeful I might see some benefit (in at least one of my cats).

It is possible that it's something in the environment too of course though. Allergy testing in Australia runs into the $400 area and from what I can tell, the skin prick testing is more accurate than bloods, however won't diagnose food allergy, only environmental.