I really have to second - or third! - the advice regarding holistic/homeopathic vets.
My Tommy was dying, even though every test from every specialist came back negative for everything they could think of to test for. He couldn't even tolerate the vegetarian food, which is supposed to be the last resort for dogs who can't tolerate animal proteins. He was down to less than 3 pounds as a puppy, and losing more weight daily. One year later he is not just alive but doing great - not perfect, still has some food issues, but healthy enough that we're not worried about him anymore. He hasn't had any prednisone in a year, either. No more ear infections, no more urinary crystals, no more skin issues, no more lethargy (although still incredible laziness
I love my regular vet, but it's the traditional chinese medicine that really saved my dog - rather than treating symptoms, the holistic vet approached it as treating the whole dog... symptoms that we didn't realize were even related or even symptoms at all were part of the big picture. The dog who couldn't eat anything before has almost no sensitivities/allergies left - we've actually just begun introducing chicken back into his diet, which he hasn't been able to eat since he was about 10 weeks old! Natural supplements combined with some aggressive acupuncture treatments saved my dog.
It may not be your solution... but it might just work for you guys.
We're thinking good thoughts for you and Bobby