I have to say that I lost a four month girl to almost the same symptoms. Right down to the odd intestine part where it almost looked like it had telescoped or accordioned. Ultrasound revealed odd "dents" on her spleen and the intestine thing. We went to four excellent vets including Ryan Hospital at U Penn. we couldn't figure it out - no abnormal cells when they drew from the lymph node. We even went through most of those same Meds. She would get better- bloody diarrhea and diarrhea would go away but would come back after we weened her off the Meds. We heard this : these could be signs of cancer but we have never seen it in such a young puppy. We had to let her go the last time we went in because her systems were shutting down. The vet at U Penn asked if she could do a necropsy because they really wanted to know what took her little life. She had lymphoma. I hope and pray that your diagnosis turns out to be different. my puppy went down hill fast after we weened her off the prednisone.
My daughter had a dog while she lived there. Hoki was a little guy from the street and she brought him back with her. I don't remember her mentioning that it really cost that much more than here in the States. I don't believe she fed a really high quality dog food though. She might have had it mailed in. If you are interested I can ask her. I love Taiwan. Hope you are seeing some wonderful things.