My cat can at different times sneeze uncontrollably. I have treated her for fleas, treated my house for allergies and she still does it. Saw the vet and he feels she may have a chronic upper respiratory issue since I found her on the side of the road three years ago in the winter, he feels there is noting more to do but get more vitamin c in her diet there has to be something for her as she is happy and otherwise healthy. I worry when she gets older as these fits do seem to take a lot of energy and can last several minutes. Not to mention when I am at work it gets on furniture and has stained some items in my house help

Has your vet tried to look up her nostrils to see if maybe she has something blocking one of her nasal passages.. my sisters cat was doing this and he had a small tumor.. no symptoms other than sneezing... did he put her on any meds?