When I was four years old my mother discovered that I was a much nicer person when I did not drink cow's milk. She took me off all dairy products and I went from miserable child to stable member of the family. When I was seven I was able to consume dairy products again, but I retained a sensitivity to them that still shows when I am under stress.
Our second child was clearly sensitive to foods in my breastmilk, presenting with the classic symptom of eczema. For The Princess we narrowed it down to dairy and chocolate. I removed them from my diet, and she grew out of it by age two.
Little Guy, our third, has been the most challenging and complex case for us yet. I eliminated chocolate, then tested it. Definitely bad. Then I took out dairy. Yup, that too. But he still was having problems. I finally went on a multiple elimination diet, reducing myself to meat, vegetables (except tomatoes, peppers and potatoes) and fruits other than citrus and berries. I took out everything that was a common allergen, and then some. After two weeks I slowly started adding things back in. Now we know he can't have dairy, chocolate, wheat, eggs and tomatoes. And that's in breastmilk! Imagine if he actually ate it!
My weird diet has forced me to get creative. We are eating a much more varied diet grain-wise. The thing I miss the most (besides pizza, for which there is no substitute) is baked goods. I have found several recipes that really work (and have had plenty of flops... eww!). I will be posting successful recipes here every so often in the hopes of helping other folks like me who have to take large categories of food out of their diets.
BTW, Little Guy is the happiest, sweetest baby, but I did not know that until I had eliminated these foods. So many of his symptoms would have been called colic, or reflux, and he would have been medicated for them. In the end such a simple solution. If you have a fussy or rashy baby, do consider food sensitivity. And if you need support, I'm here!