IF you suspect food allergies, switch him to one of the Wellness 'simple solutions' foods or to **** Van Pattons Natural Balance in either Fish and sweetpotato or Duck and potato. I've had great success with these foods and allergic dogs.
Common (food) allergens for dogs are:
Lamb
Beef
Chicken
Corn
Wheat
Soy
Rice
It's also VERY common for dogs to be allergic to environmental items such as grass, carpet, certain ingredients in soaps and cleaners. I would advise a skin allergy test to eliminate environmental allergies.
I agree, those conditions should also be eliminated and Thyroid is FAR more common than ANY allergy