Marie, thanks for your post. We adopted Stitch over a year ago now and have been dealing with these allergies since then. We have not at anytime been offered a biopsy or test. Only when I pushed our vet did he recommend the prescription diet - I think Stitch's is Hills XD? I have however been using some of the brands Sam suggested to alternate and these are equally as effective. Nothing though seems to take the full problem away, only reduces it and makes it more manageable.
Next time Stitch needs a trip to the vet I am going to demand some tests. Even if this means tears on my part. Steroids are not a long term answer but the only one I have for now. Its the only thing that seems to improve her quality of life at the moment even although longer term doing her no good. Unfortunately as we took Stitch in knowing she had this skin condition, none of it is covered on her insurance. Nevermind, if we can find some solution regardless of the cost, I'm willing to pay this for Stitch to be happy and comfortable.