Have you tried a trial of taking gluten out of her diet for a while? Eczema is one of the ways gluten intolerance can manifest. Also, are you giving her a vitamin D supplement? It could be she's deficient in vitamin D. I don't know how old your daughter is, but there are sublingual and liquid vitamin D products out there. If she is young - preschool age - 1,000iu-2,000iu supplement would be a good place to start. Children today are often deficient, because vitamin D is found naturally in only a few foods (liver is one) and children simply don't eat these foods and they don't get the vitamin from the sun as they get slathered with sunscreen to prevent burns.

http://www.vitamindcouncil.org is a good source for more information.