We went through this with our son who will now be 1 next week. We tried everything and finally found the culprit. I had to put him on Similac formula without DHA/ARA. We tried soy and protein free hypoallergenic formulas and that didn't work for him, so we were pretty certain is wasn't a milk or protein allergy. Then I read that the DHA in formula is derived from fish oils. So I found a formula without it and he has been perfectly clear. I had trouble finding it, but it is out there. And yes, DHA/ARA is supposed to supply the nutrients to aid in development, yada-yada. It wasn't in formula when we were kids, and in fact was just added a few years ago and we all developed fine without it, so I figured his comfort was worth it. After he had been clear for a few months I did try to go back to formula with DHA, and he broke out again (not instantly, but slowly over a few days). Once he was off it for a few days he was great again. He can't even have the cereal or baby food with added DHA.
Our ped didn't want us to use the rx cream on his face, only on other parts of his body. He had us use the OTC hydrocortisone cream for his face. We used that in conjunction with Aveeno Baby Moisturizing Cream. The combination seemed to work really well for him.
Whatever is causing it for your daughter will likely be hard to determine because it takes so long once the allergen is removed for them to clear up. Hang in there, and if you're thorough and persistant, you'll likely find the root cause.
I am afraid to find out what else our son may be allergic to in the future, but for now he can eat any baby food as long as it doesn't have DHA, so that's a good sign. He is showing some mild symptoms of potential asthma, which also tends to go hand-in-hand with allergies and eczema, so keep an eye on her. Our son had what seemed like a neverending cough, then one night his breathing was labored and he was wheezing so we took him right in. So far he's great and has not had a single eczema flare up since removing the DHA formula.
Best of luck to you. She'll likely be just fine, but it can be a long and frustrating road. Feel free to email me if you would like any more info on what we went through (this is already a novel, LOL). I'd gladly share our experiences if it helps... ____@____.com