Cat Scratching But No Fleas Found

Have been trying to figure out why my cat has been scratching more than usual. I've not seen any fleas and have put Frontline on her (48 hours ago) but she still scratches some . She's an indoor cat only. What else could the problem be?

  She had dry skin on the end of her back this winter and skin would flake off, she would lick there a lot and pull a few hairs out while doing it. We had an extremely cold winter, so figured it was dry skin. Can't find any fleas at all on her or anywhere she lays.  Any ideas?

It could be allergies. I suggest taking her to the vet and have them examine her

What types of things could she be allergic to?

Types of things she could be allergic to:

Environmental: House flies, roaches, pollen, laundry detergent/softeners...

Food: Specific animal protein (chicken, beef, fish...,) Corn, wheat, rice, carrageenan, guar gum...

She could have developed an allergy to anything. Even something she had been exposed to for a while.

Mine turned out to have a chicken allergy under similar circumstances. The difference in his coat is the most interesting result of eliminating the chicken. It is very fluffy now and needs far less intervention from me.

It is probably allergies, my one cat has allergies and has scratching and watery eyes.  I now have her on L-Lysine that you can purchase at any health food store and I sprinkle a little on her food - it has helped.  She suffers most in the spring and fall, she only itches on her head no where else.  I also changed her litter this year to a less dusty litter (crystal) and noticed that her eyes do not run so much as they used to.  You might take to the Vet just to confirm it might be an allergy or could be an eye issue.