Hello I have a 3yr old girl of mixed races who has had

Hello I have a 3yr old girl of mixed races who has had exzema off and on since birth. I havent found anything that works, but Iam lery of trying things I find online. The only thing that did work was a vacation to my families country of Croatia. The water from the Adriatic sea transformed her skin. Her trouble spots are ankles, behind the knees and inside of elbows.
I would greatly appreicate any advice.
Thank You
doris