Haven't had any experience with your skin problem, but it does sound like you're trying a bunch of different things. Perhaps the remedies are aggravating the original problem? The above suggestions by everyone sound good.
First of all, welcome tot he site. As a newbie myself, I have found it very helpful and everyone is so cool. As for the eczema, one of my kitties has a dandruff problem. The vet told me to rub a little olive oil on his coat every once in awhile. It has seemed to work. I don't know if this would work for you or not.