Cocker Spaniel with rash

Question
I need advise on how to handle my cocker spaniel's rash problems. I am tried of professions saying "he is a cocker in Florida,he is going to have skin problems".  Here is what is going on. He gets bumps, I believe the start off red, then they seem to break and get scabby. If I pull the scab off then the surrounding hair will come off also. A board certified dermatologist, started him on Atopica, after one month he was rash free, but lethargic, which I did not care for. So she reduced his dose. Which he would still break out but not as badly..for few months, then he really broke, so we went to the vet. The vet put him on 500mg cefalexin, 200mg ketoconazole, 20mg predisone, plus we continue giving him the Atopica. This continue 90 days, once the vet felt Sammie system was calm, we did an allergy test. Come to find out he is allergic to most everything, especially the food I was feeding him and his favorite carrot treat. So now he is on a Venison and Potato only diet, Atarax 50mg 2x daily,Atopica 50 mg for dogs weighing 16.1 to 33lbs daily (Sammie weights 54lbs), and Interceptor and comfortis for fleas and heartworm (he took him off the revolution, however he is not allergic to fleas.  Needless to say I am spending roughly $260 a month and you guessed it, Sammie is breaking out again. Plus he gets bathed weekly. I am at wits end, what can be done for this sweet boy of mine?

Answer
I know just how frustrated you are.  I have some questions.
First - has anyone tested his thyroid?  
Did the Dermatologist try a trial of Vitamin A?
Suggest topical approaches for comfort (oatmeal soaks - vinegar rinses - anything?)

I'll need to know a lot more Peggy but your experience with vets and medications aren't unusual.  Right now he's on a whackload of medications and, by the way, is way overweight.  

Has he been overfed?  If not and he gets enough exercise then that's a hypothyroid symptom.  Add the skin problems to that and any good vet should have instantly run a thyroid panel.

I'd really like to talk with you at length directly.  If that would be helpful, do write me at DeeBeck7765@aol.com.

Also:
How old is Sammy?
How long has this been going on?
Did your vet do the allergy test or the Dermatologist?
Was it a blood test or intra-dermal skin testing?
Is he itching?
What shampoo are you using?
Is his coat dry & scaly or oily?
Delores