Hi Dennis,
This case seems ideally suited to San Ren Tang. The formula is commonly effective in Silky Terriers, and addresses colitis, vomiting, loss of appetite and crystalluria in dogs with deep full (wiry) pulses. It's one of our favourite skin formulas, too.
If it works well, then I'd look at a grain-free home-cooked diet, if at all possible.
Hope that helps you out,
Steve