How To Cure Eczema In Toddlers?

Hello, i'm afather of 4 months female baby, she have infantile eczema since 2nd mth of her age , on treatment topicaly H.C. 2.5% cream 4 times daily with systemic cortisone 5ml 3 times daily+ anti histamine . for 10 days untile now
the quest. is: why when start to decrease the dose and try to take it off the skin rash and redness flair up again, and for how long can i use th corticosteroid specaily when i'm adoctor (orthopedist) and know the side effect of long use of it.
please tell me what can i do for her and thanks