I'm so sorry that you are still having problems with this. You mentioned that your doctor thought that it might be eczema. Even though you doubt this, have you looked through the eczema forum to see if you can find any helpful guidance there? Maybe others there have had similar symptoms and can offer some help:
(The eczema forum sometimes doesn't come up on mosaic that often, so I wanted to be sure you knew about it.)
If it turns out to be a fungus, there are also prescription topical antifungals, such as 10 percent Lotrimin that might help. They are stronger than over-the-counter antifungals.