Eczema is the reaction to exposure of a substance for which the immune system is intolerant, but exposure is not the cause of the intolerance. As I explained in

Eczema is the reaction to exposure of a substance for which the immune system is intolerant, but exposure is not the cause of the intolerance. As I explained in more detail in my other comment, over exposure to the tomato may stress the immune system to the point that symptoms become severe, but the tomato is not creating the original intolerance.