I was diagnosed after I went through the entire allergy testing. I began playing soccer when I was 15, and when I was outside, my face would burn and itch. I get hives behind my shin guards, and even sitting on the grass would irritate my skin more. It was intolerable for me.
They poked me with everything they had. I got two blood tests done to double check, and everything came back negative, even the reactor was negative. It all came down to that the heat, stress and my own sweat came into play.
Come to find out, I live with this autoimmune disease that made it hard to do much. I was told to take 1 Zyrtec a day to calm it on hot days (add 1 Pepcid), and if it gets worse double them to control my hives.
I also live with chronic urticaria and asthma. CU has also interacted in my throat causing it to itch and alter my breathing with excessive sweating and heat. But now I am 18, and I have went two weeks to check if CU went Dormant on me finding out it is still active.