We had a problem similar to this when our guy was younger. We went crazy trying to figure out what it could be. We had to treat a staph infection that had developed because of the scratching with almost 2 months of antibiotics and a special antibiotic shampoo (Chlorhexidrine I think) which he was bathed with 2x a month. We also switched his food to the Natural Balance Fish and Sweet potato and started supplementing with EsterC and a can of sardines to start boosting the immune system.
If you're concerned it's a food allergy I wouldn't use the Ultra premium formula because it has lamb and rice in it just like your old food. The idea with food allergies is to get away from anything that may be causing your dog's allergies. (This includes your treats too) So I would go with either the fish and potato or we also use the venison and sweet potato.
The biggest piece of advice I got from people was to boost the immune system, so your dog has a better chance of fighting the allergies on their own. So far we've had a lot fo luck with that and seem to be allergy free so far this season.
EDit to Add: I seem to remember seeing something not too long ago about how sweet potatos were preferable to regular potatos, something about potatos and arthritis...maybe someone who knwos better can chime in...
If you're concerned it's a food allergy I wouldn't use the Ultra premium formula because it has lamb and rice in it just like your old food. The idea with food allergies is to get away from anything that may be causing your dog's allergies. (This includes your treats too) So I would go with either the fish and potato or we also use the venison and sweet potato.
The biggest piece of advice I got from people was to boost the immune system, so your dog has a better chance of fighting the allergies on their own. So far we've had a lot fo luck with that and seem to be allergy free so far this season.
EDit to Add: I seem to remember seeing something not too long ago about how sweet potatos were preferable to regular potatos, something about potatos and arthritis...maybe someone who knwos better can chime in...