Even if your cat has no visible signs of fleas, it can still have flea allergy dermatitis. Your cat can even have it if you give it flea medication. A quick .pdf file for quick reference if you want. Tis the season for it if you live in my area.
http://nutroproducts.ning.com/forum/...rgy-dermatitis
http://nutroproducts.ning.com/forum/...rgy-dermatitis