Its the chicken or the egg syndrome. We who have these "allergic" responses can have genetic mutations in methylation pathways via the liver. I had this tested out of pocket and it has saved my life.
I am a slow metabolizer in the P450 CD6 enzyme. With these tests it will come with a list of meds that you should or should not take with the dosage for your doc. It comes with a software that I or my doc can type in all my meds to see if I will react and if there are any contraindications with each med together or separate. Having a P450 CD6 mutation is why I cant take morphine/codeine or most anti-depressants. These tests are now being used by hospitals sometimes or at least when i hand the results over now they know what i am talking about. Five years ago they would say " oh, I quess you cant take that"!
This can also be a mitochondrial mutation. There are 3 centers in So. Calif. UCSD, UCI, UCSF. They can do genetic DNA tests that can pinpoint what is mutated, damaged, or missing in your mitochondrial cells. This is cutting edge and has a huge piece of the puzzle for things like RSD, MS, Fibro, diabetes, etc. which i personally still think sets us up for these syndromes. I will let you know what happens once I start in the center at UCI. I'm doing this for my children.
The genetic counselor asked several questions and one was does anyone in your maternal side have droopy eyelids. I was amazed because my mental picture of my grandmother was her holding her eyelids open with her finger. My mom had it and I have some too. She said that was a marker for mito disease. Ha, I thought it was just getting old LOL! I told her about TOS/RSD/Fibro and she said it is all mito mutations. Environmental factors are huge as well in damaging the mito. She stated that you can be pre-disposed and then WHAM a trigger can start the cascade.
She stated they think that they can correct these diseases in the next 5-10 years God willing.