My Beagle has the same, smelly ears, itching and shaking her head... Vet did a swab and it's yeast, he said it's very common esp on long eared dogs and at this time of year. He gave us some drops but a breeder also recommended to us to avoid kibble and feed home cooked or raw food diet. Apparently she had a lot of problems with one of her Beagles and this helped him.