I am writing about the Human Animal, and Yeast. This might not apply to Dogs, or Cats. We are all warm Blooded, so it might apply. In Humans, the over-abundance of Yeast can mean several different things, but the top reason for us, is diet. In Humans, it can also mean Diabetes. With Animals, I would say that it's Food Allergies. It could be the Corn, or the other junk that is added to the less expensive Foods. Some Dogs are allergic to the Chicken. My Dog was an itchy Dog. We went Grain-Free, and she no longer itches. Try switching foods, and give it a couple of months, and see what happens. Friend's of ours have Labs that constantly had Ear Infections, and they switched to Taste of the Wild. Neither one of those dogs have had an ear infection since, and it's been years!!