My old boy William, who I lost just a couple of weeks ago at almost 16 years old, was always itchy when young and had recurring ear and lip fold infections, dry skin and a sensitive digestion for the first 5 years when he was kibble fed. We tried a variety of kibbles, including ones that were described as hypoallergenic, but he continued to have problems.
Before William came along I'd always been a raw feeder because that's what my first Cocker pup was fed on when he came to me in 1987. But when William came to me his breeder had fed him on kibble and my vet recommended it and basically told me my ideas were old fashioned and that kibble was the best way to feed.
It took me 5 years of thinking I had a dog with more than his share of health problems before the penny dropped and I stopped feeding kibble and started feeding raw. I can honestly say it was like waving a magic wand because within days his skin and digestion were a lot better and his ear and lip fold problems stopped, never to return until old age and even then only infrequently.
I'm not saying it's the solution for all dogs, but it definitely worked for William.