Oh my gosh, poor baby
!
The IBD is a possibility, and I would have a chem panel done (or review past ones) to see if it indicates it. It sounds like she has both upper and lower involvement.
I just did a search and found a great page for you to read regarding IBD:
Inflammatory Bowel Disease (IBD) in Dogs. If it is IBD, one of the best things you could is consult a canine nutritionist. I worked w/ one (via phone) for my Marcel (and others here at YT have now used her too). Other members, EllieMay and TLC have also used other nutritionists. A nutritionist can really work miracles sometimes - she did w/ my Marcel.