HiCustomer

Sorry to hear about your cat's skin problems. I'm going to be honest here in saying that the Hartz flea drop is not the best flea preventative medication out there. In fact, there have been some cats that have had very, very serious reactions to it. I know it costs less than the medications that you can get through your veterinarian, but paying a little more for a product that is safe and definitely works is worth it.

In your situation, I would definitely keep a very close eye on your little one as far as a reaction to the flea drops placed on her. You definitely need to make sure it was a product for cats and not for dogs only.   I have seen way to many flea preventative toxicities due to the fact that a dog product was placed on a cat. If this is the case, bath her and wash off as much of the product as possible and contact your vet. If it was a cat product, then watch for any tremoring or twitching or lethargy - if seen wash her and call your vet.

Since her hair is still falling out and she's itching - I'm going to say that one of these could be going on. 1) She still has fleas. 2) She has a secondary bacterial infection on her skin. 3) She could have ringworm. 4) Some other skin issue. My best recommendation would be to have your veterinarian evaluate her and start up appropriate therapy based on what they find.

Here is a link talking about flea control.
http://www.VeterinaryPartner.com/Content.plx?P=A&S=0&C=0&A=1575

I hope this helps.
Dr. Bruce