@Critterina I honestly do not grasp the science behind any of this but I have a phenonemal doctor who is an allergist/immunologist and one of the few true mast cell/MCAS specialists in the US and I was so lucky to find him when I did as he is now closed to new patients.
I tried all kinds of meds and treatments prior to starting with him and the most helpful medication for me for MCAS is Ketotefin. I know I could probably eat more foods than I am now but am being incredibly cautious and add just a few new foods each weeks (all zeros or ones on the list.) I have not yet tried any food that is listed above a one. My most severe reaction was to Tartrazine (yellow #5) and FD&C and AZO food dyes which I suspect will be out for me forever.
The nebulized glutathione is so highly recommended for me by the mold specialist I am working with that I would have tried it back in June if not for the MCAS. She felt given my total picture it is only safe for me to try it in the hospital setting and it has been a long process to coordinate but I am very close now! As soon as it is called into the compounding pharm and I do the sulfite urine test strips, I can schedule an appt to try it.