Ok so I got a cat a little over a year ago. He was normal at first. Then as he got older he started developing very bad breath odor. I didn't really worry about it until he started getting scabs all in his ears. My dad thought he had ear mites and I looked it up and that is what I thought too so I got medicine from the store and started giving him drops. It got somewhat better, but only when he was on the drops. Then he started getting bumps on his head. The hair on his head started falling out, at this point I got extremely worried. I gave him a bath with cat shampoo and washed everything in the house, and he got somewhat better. I took him to the vet and he was tested for FIV and Feline Leukimia they were both negative. They put him on antibiotics bc he had ulcers in his mouth. His breath got better, but came back as soon as the antibiotics were gone. Then the scabs came back and soon turned to sores. Things seemed to get worse and worse. Pretty soon he had sores all over him. I took him to the vet again, still more tests. Parasites--negative. Nothing wrong with immune system. No feline aids or feline leukemia. Eventually, he had open wounds all down his back. I could not afford any more visits to the vet. I was heartbroken and had to take him to a shelter. At the shelter they told me that there was nothing that could be done at this point and that he would have to be put down very soon to end his suffering. I was so upset.
I shampood all the carpet in my house. Cleaned all the walls and floors in every room. I cleaned EVERYTHING! After a few weeks I got a new kitten. Now after having my new kitten a week or two, it is now showing signs of the very same thing as my old cat. I do not want to get rid of my kitten. I can not afford anymore tests to be done. I do not know what to do. Does anyone have any knowledge of what could be happening to my poor pets? Could it be something in my house that could be hurting me also?

I am out of ideas! HELP!