The only time my dog gets these is if I try to change her dog food or I change to a new treat. I'm going to guess and say that it's food allergy related. Just as an instance of how my dog reacts, here is her latest food allergy story; I bought a bag of Chicken Soup For the Dog's Soul treats. I gave her a couple a day, they are very small little heart shaped treats that you can break in half, about as big around as a quarter. She was doing well on them so I got kind of carried away and started giving her about 6 a day and noticed that she began to scratch and gnaw and she had "pimples" on her chin. I knew right away it had to be those because there was nothing else new. I stopped giving them and immediately all her scratching and pimples went away. She is very allergic to rice, the treat did not have rice but it has barley, I'm just guessing that the barley or maybe the oatmeal is her issue in this treat.