Thank you for your question. You are definitely taking the correct approach for your daughter as plant based diets are greatly beneficial for eczema. Unfortunately this does not mean that all cases of eczema can be treated completely in this way. There are other potential environmental triggers for eczema that can be difficult to pin point. There may even be some components of plant foods that can act as a trigger like gluten so it may be worth consulting an allergy expert for skin patch testing. I understand your concern about using steroid creams but short causes of low dose steroids should not have any long term effects and sometime are crucial for getting the condition under control. I do agree that many children grow out of childhood eczema. Don’t forget to emphasise all the healthy components of a plant based diet – whole grains, legumes, fruits and vegetable and avoid refined sugars and added oils.
Although this article is mainly about asthma, the same principles apply for exzema
A more novel form of treatment involves exposure to broad or narrow-band ultraviolet (UV) light. UV radiation exposure has been found to have a localized immunomodulatory effect on affected tissues and may be used to decrease the severity and frequency of flares.   In particular, the usage of UVA1 is more effective in treating acute flares, whereas narrow-band UVB is more effective in long-term management scenarios.  However, UV radiation has also been implicated in various types of skin cancer, and thus UV treatment is not without risk.