So, we never really did get to the bottom of DD2s "eczema".
So, after cutting all the major allergens from my diet, we finally started to see a change. This was also around the time it stopped snowing and started raining, so everything was moister anyway. And, we'd been using Aquaphor to moisturize her religiously. This was also the time I finally was able to get DD2 in to see a dermatologist.
She told us it wasn't eczema at all, it was hives, and showed us how as she touched her unaffected skin, you could see a histamine reaction.
So, I took her to an allergist. The allergist agreed it was hives, and said there might have been eczema there once, but it was now all hives. She said it did NOT look food related. She didn't want to run any tests due to the high risk of a false positive. Apparently, false positives on food allergy tests are common and a positive has to be correlated to an actual reaction to food. DD2 is way too small to do that, and while she has started solids, this isn't a good path.
So, she had me start to add back all the food I had taken away - one food a week and wait for a reaction. If none, add back another. I have added everything back except peanuts to date.
Her best guess is DD2 inherited my allergies, and that we can correlate. A couple of times when we went out for walks and I ended up with a bad reaction such as hives, so did DD2. *sigh* I told DH his one job was to make sure any kids we had didn't get my awful allergies (he has none).