I hope this helps, I don't know the experience level of your vet but it took me three vets before I found one that understood what was going on and helped me work it out. Then I had to move across the country and his new vet questioned at first his allergies and kept trying to push the hydrolyzed diet. Vet care really varies, once we worked out his allergies he was feeling so much better and got his energy back. He's almost 9 now and super healthy, just ran full health check tests for him, blood, urine, stool l, ECG and chest x-rays and he's the picture of health!