Well, I have had contact dermatis caused by nickel in jewelry most, if not all of my life.
About ten years ago I developed eczema and it became very severe-over most of my body, extremely uncomfortable, with bad patches that oozed and became infected. I was on triamcinalone and clobetazole cremes (sp?). I started noticing that it was much worse after eating certain foods, like chocolate and citrus fruits. My dermatologist told me that some studies had shown that some people who reacted to nickel contacting their skin with dermatitis also reacted to foods high in nickel.
I found out which foods were high in nickel and many of them I instanty recognized as problem foods for me. I went on a diet low in nickel and my eczema improved dramatically. If I consume any of those foods it comes right back. Just a tiny bit of chocolate does it.
My dad had the same type of dyshidrosis as you, huge blister on the soles of his feet and palms. He never figured out what caused it. But you might try eliminating nickel in your diet. It's very hard to do but really helps me.
Also, I researched and found that excess nickel in the body binds (chelates)to something in cilantro so I make a paste with cilantro, garlic and olive oil and eat that to help my body get rid of excess nickel. It seems to help. Good luck!