After numerous visits to vet with scratching, skin sores, inflammation, and yeast infections my shepherd mix's medical root cause was determined to be a low thyroid. He is now on low dose of thyroxine which helps but at onset of spring he still had a severe skin flair-up. My observation is that his recurring yeast infections manifest from an overgrowth of yeast in the gut that he cannot balance due to his poor immune-system. After listening to a lecture on probiotics from a doctor at recent dietitian conference I decided that this was worth a try. I have now had him on Mercola's probiotics (human dosage) which had 70 million flora and I do believe it seems to be helping. My philosophy is it can do no harm. His itching is waning and he's resting better, less anxious. Not sure if this is the answer but I believe it is a part of the answer. The right probiotic helps restore the yeast imbalance caused by the complexity of a immune-system run amuck.