Try taking fish oil capsules (with food so you don't get such a fishy burp later - trust me!) and eating more oats. You could also try putting oats in your bath, not actually IN really, but running the water through some in a cut-off pair of tights. Sounds bonkers, but it can be really effective for the itching!!
The no-dairy thing is a definite one to try first. Then try wheat second. (Check labels on food as these both crop up everywhere.) Think of any outbreak externally as your body trying to tell you something isn't right internally - meaning it's probably finding it hard to process something you eat regularly. Sort the problem from the inside out, or you may be using creams forever! When cutting these out, be really ruthless for a few weeks to make sure you can be sure your experiment is worth the effort. You probably won't have to give up the offending food (if there turns out to be one!) forever anyway. It could just mean that you are aware of your trigger(s) and know what to expect in future. With dairy and wheat likely to be a large part of your normal daily diet, sometimes going without can clear your system and give it a chance to relax and not work so hard for a while. Afterwards, you could just try to eat them more sparingly - that way your life goes on normally! It's worth giving it a really serious go - it's worked for me. It doesn't mean an allergy (yawn, yawn!! Just watch people's eyes glaze over if you start on THAT subject!) just something your body finds tricky. I try to have wheat only a handful of times a week, or none if possible, and oats all the time (porridge - yum!) and my skin hasn't given me ANY trouble for about 9 years now, promise.
Give it a go - good luck!!
ps Other foods on the list of culprits could be citrus or tomatoes, but only exclude one thing at a time, or you'll get confused!