It was ruled out early on, along with fungal infections, HIV, etc in an array of tests. Basically every test I've had has come out clean, minus occasionally a little high blood pressure. And the IgE levels in orbit as mentioned above.
I had a look at the symptoms and I don't think it matches what I have. I believe my urine and stool test would have ruled out high mediators, although I can ask my GP next time if they were checking for that or not.
Ultimately I think my solution will be to go to a tertiary/quaternary center like Duke.