Can people be allergic to cat hair?

It's not actually the cat hair itself that people are allergic to, but rather a protein called Fel d 1 that is found in cat saliva, urine, and dander (dead skin cells). This protein is then transferred to the cat's fur, and when people come into contact with it, it can trigger an allergic reaction.

So, while people aren't technically allergic to cat hair, they are allergic to the Fel d 1 protein that can be found on the cat's fur.