I went through a period with Tiger with intermittent sneezing periods and a watery left eye a while ago. He would also shake his head as if he was congested.Cats can get allergies, but the symptoms are generally itching and overgrooming, not sneezing. If one of my cats started sneezing frequently, I'd have my vet check his nasal passages for polyps or foreign bodies like weed seeds.
Arm & Hammer carpet deodorizer caused one of my cats to lick all the fur off the base of her tail, and it took me a while to figure it out too. The vet said it was an allergy, possibly to chicken, so I was supposed to force her to eat this duck and green pea wet food. She starved herself for 36 hours. Since I never thought it was a food allergy, I gave up and thought about environmental issues. And it finally occurred to me that the only thing I'd changed was to start sprinkling that powder on the carpet before I vacuumed. Ironically, I believe the product was specifically a pet odor deodorizer.Shortly before this I had used arm and hammer carpet deodorizer powder on his cat tree.
I'm fairly sure this was the reason for Tiger's issues .
The whole time he had the issues I lived in an apartment with carpet and sometimes used the carpet powder.
I then moved into an apartment with hardwood floors and up until the time I used the powder on the cat tree he had been symptom free .
It took me a long time to piece this together and thought I would share .