Why does my cat scratch himself and create sores?
He has sores that ooze blood and he is loosing his hair, but he scratches it so bad he makes them bleed. He leaves hair attached to the scabs all over the house, but he has no fleas.
Fleas aren't always that obvious, but flea allergy dermatitis is not the only reason cats scratch, either.
If your cat is scratching excessively, it could be a sign of stress. It also could be a food allergy, or a contact allergy to something in the environment, or some other medical condition.
When Jazzy eats too many of a certain treat, he gets bald spots, and begins scratching and licking himself excessively. Each time this has happened, I cut off his treats before it got too severe, and the problem went away. That's how I figured out it was the treats.
If your kitty is scratching himself to the point of bleeding, I would suggest taking him to the vet for a proper diagnosis. Be aware that if your vet suggests it as part of the treatment, there are certain risks to giving a steroid shot to a cat