Oh man, sorry you and Maximus have to go through this. I've been following all your threads mainly because Stig showed the exact same symptoms. First it was a small hot spot which got bigger, then hives, itchiness, raw wrinkles (you can find the thread about it here), mange as a secondary reaction, really pink skin, etc etc. We were at the vets at least once every other week, sometimes twice a week. He was on antibiotics for 3 months when the vet finally decided to stop giving them only because Stig was getting ear infections! The antibiotics were for his hives so they wouldn't get infected. They also dried up and scabbed as what you describe above. I don’t even know how many bottles of Benadryl he went through. It was awful, and my bf and I felt like the worst parents in the world. We were even thinking of giving him back to the breeder at our expense because we saw that he wasn’t getting any better.
We did the food trials, from the breeder’s choice of kibble, to wellness, to orijen and then to fromm salmon. The fromm was the best out of all of them but his allergic reactions were still apparent. We even changed the detergent we use and his shampoo to oatmeal and aloe, however, nothing changed. It was by chance that we learned about the raw diet from Stig’s doggy daycare owner when we enrolled him. We were extremely hesitant at first as we questioned the bones and the germs (salmonella, e-coli, etc). After doing extensive research, asking numerous questions and seeing how Stig wasn’t getting better, we decided to give it a try. Literally, we started on raw on a Sunday and saw positive results by Monday. All his hives disappeared by Tuesday. No joke! It was such great timing because we were going to do the costly allergy test on the Thursday. After a few days, the hair on his wrinkles grew and his tear stains decreased tremendously. His hot spot got better and he stopped scratching.
I’m not advocating rawfeeding, it’s definitely your choice. But I wanted to share what I learned from this experience. When doing food trials, absolutely only feed him 1 type of kibble. This means no treats (even if they’re grain & gluten free), fruits, veggies, not even yogurt or pumpkin, cheese, etc. NOTHING! You need to isolate to one specific kibble only. If you feel you need to provide treats, then you can use the kibble as the treat. If someone would’ve told me this sooner, our lives would have been much easier. I remember it being painful because we had to throw away bags of kibble and treats that were still more than half full. But it was all worth it in the end. His current diet consists of raw meat for meals, dehydrated meat for treats, as well as fruits and veggies. He can even eat peanut butter, yogurt, pumpkin and such. And he’s MEDS FREE! We haven't seen the vet for his allergies since November! He was so surprised and impressed when we brought him in for a checkup the day we cancelled his allergy test. We have no clue what he’s allergic to but know that he always reacts to kibble food and any store bought treats so those are the only items that we stay away from.