Thanks Hercules Dad and YorkieGirl2 for your quick responses!
YorkieGirl2, in response to your question about itching. For the first couple days, Bart was scratching his one ear - but that seems to have tapered off unless I'm so obsessed about his sneezing nose that I'm not noticing the ear scratching any more.
We do live in an older house - mostly with hardwood floors and area rugs - so perhaps dust is the culprit. Having said that, Bart never sneezes when he's sleeping, but I've been preparing a hot water bottle for him at night and for his naps. Perhaps the warmth helps?? If it were allergies, would he also sneeze while sleeping?
Hercules Dad, I think your suggestion of a 2nd opinion is a good idea. I like our vet, but telling me it's a collapsed trachea without any sort of real examination or test, seemed like a quick judgement to me.
We'll see. It's so heartbreaking - especially when they're so sweet and cute!
Thanks.