Our story was similar to what Anna Maria Smith is saying... so I can give you an example.
We had a derm that said diet absolutely didn't matter, would make NO difference whatsoever. She had us using steroids like triamcinolone and more potent over the years.
My son started flaring when not using and my son eventually became red/itchy all over... from eczema that started only on his hands? He developed infection after infection and needed an inhaler pre-sports and when sick. When he was 14 he stopped growing, we had to reach out to an endocrinologist as he was suddenly the smallest kid in the class.
Labs were done, and he suffered from Adrenal Suppression from the steroids that we used as directed - 2-3x per week. The adrenal suppression was so bad that our endo told us how dangerous the steroids were to the body (his adrenals has almost failed) and that we had not choice but to stop using them, with her guidance.
I researched and quickly then discovered others that had similar issues with adverse effects from steroids.
He did go through Topical Steroid Withdrawal, and it has been a long journey. He is 17 yrs old, so not exactly something a teen wants to go through. But, like many others we didn't have a choice. We met with a Natural Healthcare Ph.D. who told us to remove many things from his diet.... wheat, dairy, sugar, corn, egg yolk to name a few. His skin, 18 mths later is beautiful.
I haven't seen it so clear since he was a baby.
He hasn't had an infection since stopping steroids and his cortisol levels are within normal range. He has grown 5" but we do notice that if he still eats food with dairy or Sugar and a few other triggers he will itch & flare slightly.
So, in some cases steroids are not the answer but more of a bandaid to suppress the symptoms, do your research - I wish we had not listened so closely to our *former* derm.
Changing diet is a lot of work and requires patience and lots of label reading/creative cooking, but if you can try that first and eliminate the steroid use then in the long run, in my opinion, your child will be a lot better off.