Childrens Sunscreen and Excema - Not a Good Mix?

Ok - this is a plea for info from you with children that suffer from Excema.  Which sunscreen is less likely to irretate?

A catch 22 situation - dont let them go out in warm sun without sunscreen - then they get irretated by the ingredients in the childrens sunscreen itself! 

So - feedback please on which product you have found most effective in situations like these.  There is nothing worse than 3 and 5 year olds that dont understand why they cant play outside in the sunshine!