Was told to cut dairy from my daughters diet cause it causes eczema?!?

So my daughters pediatrician told me my 15mt old daughter has eczema. She said to use a lotion called cetaphil, as I was browsing and looking up more info on how to help get rid of it one article said to remove dairy from her diet because it has been known to cause it!? Just about everything she eats is dairy. Does dairy really cause eczema?? I don't want to cut eggs, milk and cheese out of her diet unless I really have to.