
I would have a blood test done - my dogs results were positive to HDM and flea saliva. A strict elemination diet could help you work out what if any the food intolerances are - long winded and very strict but this could be done without any vets fee's. Skin scrapings can be inconclusive but blood tests are more accurate. If it were me, I would see another vet and ask if they could get to the bottom of it, after all, allergies don't go away and this could be a problem you will have for the whole of the dogs life, also, very distressing for the dog. Good luck