I forgot to mention my recent experience. Little Reno has these sneezing fits every once in a while. I probably hear one a day, she'll sneeze for 60 seconds repeatedly and then she's fine. A vet trip resulted in antibiotics...which didn't help, and an end diagnosis of allergies. You are in a similar climate I think so maybe, that's what is bugging Josie too. I also noticed a decrease in her sneezing since we moved into our new house. So I think our older house had more dust etc.

This sounds corny but, maybe that Allergen reducer Febreeze might help??

good luck!