yeah, i found most foods aggrivated it more i had to eat mainly chicken and loads of veg! yoghurt was also a no no and pastries too!
washing powder is bad, polyester or nylon school trousers and shirts dont help, you just cant win!
a shool friend who also suffered got some aqua theraph for his and it seemed to work a treat. might be worth looking into. my parents couldn't afford it for me so i had to put up with steroid based creams! and that thins your skin, so when you have a little scratch... it bleeds!!!???.
it's a case of trial and error MB but you will find some things are worse than others, good luck with it all,
how old is he? 7?