Hi S.,
It could, of course, be anything that is causing your symptoms, but it sure sounds like a very common form of eczema that VERY often accompanies gluten intolerance. It's called dematitis herpetiformus. My sister-in-law and 3 friends have this. For many people this is the only symptom of a gluten problem. You can have gluten intolerance without having celiac disease. Here's a quick blog link that you may find interesting.
http://www.glutenfreeforum.com/index.php?automodule=blog&...
4 of my husband's family members have celiac disease and my kids have the gene for it. It is very heriditary! Since we tested them at birth with a simple cheek swab, they have never had gluten. They have both recently tested intolerant of dairy, soy, and eggs. This is faily common for people with gluten issues. It makes sense that if your body has trouble with one protein, it might struggle with others.
There are tests widely available (cheek swab for gene testing, blood, stool, intestinal biopsy). I suggest you find a doctor who is an authority on food intolerance (NOT ALLERGIES!) and get some tests done. Enterolab.com is widely used among doctors who know about it. Check out their website for lots of info and statistics about food intolerance. You can even order tests yourself if you feel comfortable with that. If you are in the Boulder area, you might try Helios Integrated Medical Center.
I could go on and on, but lucky for you, I won't...or maybe I already have. If you have any desire to do so, feel free to contact me directly. I have a very large collection of GF, dairy free, soy free, egg free, nut free, etc recipes I would be happy to share. In June I am offering free cooking classes in my home in Louisville. Best of luck.
Cheers, L.