Okay here's one of the only things that's worked for me so far, in that the eczema actually stopped being inflamed, oozing and started healing.
Try fasting on nothing but granny smith apples for three days (that's how long it took for me to see results).
Now it may not be a cure since I don't think I can live on just apples for the rest of my life, but it might help you narrow down the possible cause of your eczema.
I hope your eczema heals. :)