My ACD started to have itchy problems when I switched his food. My vet and I determined that he was suffering from a food allergy, switched him to a hypoallergenic food, which helped him a whole bunch, but will still bite and scratch himself when he is under a lot of stress. Which, unfortuntaly, is going on right now with me having a lot of medical issues going on right and I am currently going through chemotherapy (at the age of 21). Chance doesn't know exactly what is going on, but knows that something is up with Mommy and he doesn't like it! Try giving him some benedryl, I would suggest one pill once a day for a large dog, half a pill once a day for a small dog. BUT I am NOT a vet, and would def talk to your vet FIRST before starting that. And just to forewarn you, the benedryl could have two effects on your dog: either make him real sleepy or very very hyper!