Got scratched by a cat 8 years ago, could it have made me allergic?

So, I used to hold cats all the time, and nothing ever came of it, long hair, short hair, it didn't matter. Then one day I'm holding a cat, and all of a sudden it scratched me, pretty deep. I didn't feel anything that night. But whenever I went around cats I had an allergic reaction. It didn't just start, it happened since I got scratched. Wondering if there is an explanation, or if anyone else has experienced this. I've wanted a cat, but couldn't get one because I believe I'm allergic.