Hello Stefanie, I'm Dr. Deb.
I recently came online and see that your question about Kitty hasn't been answered. I'm so sorry that you've had to wait for a response,but if you still need assistance, I'd like to help if I can.
What an incredibly sad situation:(I'm assuming that Kitty was tested for Feline Leukemia and Feline AIDS? If she wasn't, then I would suggest that this testing be done since either one of these conditions can affect the immune system and retard healing. If she's positive for either disease, then this could explain her current symptoms.Even if these tests were done and/or they are negative, I have to suspect that something else is going on with her systemically if she's not acting unwell. Most cats with skin allergies (for whatever reason) typically are still acting fairly normal. They may look pretty rough around the edges but they otherwise are still eating and not lethargic.I've seen a quite a few cats with food allergies who are itchy to the point that they create significant lesions on their body (often involving the neck/face/chin) and often changing the diet to one which is more limited ingredient or hypoallergenic can be helpful. Drugs can help some but are not usually 100% effective in controlling the skin issues until or unless a change in diet is made.But, the enlarging mammary masses are concerning as well although I'm not certain if she might be pregnant? or if this is simply a benign condition called Mammary Hyperplasia? or possibly cancer.From the sounds of it, you have done your best for this poor girl but it also sounds like she has more going on with her than just skin issues. Under the circumstances, if her quality of life is poor, it might be time to made a final decision about her as difficult as that may be.One other alternative you might consider would be to contact local shelters to determine if she is someone they'd consider accepting given all of her potential issues. It's probably not likely, but at least you could ask.I'm so sorry that my answer can't be a more positive one but this is a really tough situation for all involved.I hope this helps although my apologies for the delayed reply. Deb