It isn't fleas. My vet thinks it's bacterial but he did a fungal culture to be sure. But the results won't come back for 2 weeks because the fungus has to grow. The fact that none of my other cats have it leads him to think it's probably bacterial. I'm to call him on Monday to let him know if it's better or worse while it's being treated. He gave me wipes, similar to Stridex pads, to wipe over her several times a day. And she's on Zeniquin and Chlorpheniramine. While he was examining her, he could pull the hair out in clumps w/only the slightest tug. He said whether it's bacterial or fungal, she has a bad infection of the hair follicles. I pray it isn't fungal because that could mean ringworm. Good grief. So, keep your fingers crossed that it's bacterial, as if that isn't bad enough.