My IVIG flares my MCAS. Both my doctors think its my autoimmunity problems (POTS, MCAS) fighting with it each time, though the general result over the past 8 months with steady improvement - my POTS is much better.
I saw my dysautonomia specialist yesterday..He's having me on propranolol and Mestinon together. Both compounded without my allergens.
I trialled both in the last 8 weeks. Mestinon (pyridostigmine) helped my POTS a little better but spiked my blood pressure to a steady 157/95, while the propranolol helped a little less and lowered my BP to 89/55. So, he's trying a small dose of pyridostigmine with a higher dose of propranolol, to improve my POTS, but keep my BP and heart rate stable.
He explained with my BP and pulse so fast, untreated, my heart isn't filling up with blood, so I get hypoperfusuon in my brain - I fell asleep during a 10 minute tilt table test.
As for the MCAS flare, my ME/CFS specialist has me on Solumedrol the day of, dexamethasone for 4 days after, plus ketotifen, fexofenadine, both compounded, plus Zantac and quercetin. My ND has bumped up my vitamin C, folate, B12, and B5 to help the mast cell chemicals go away faster - all hypoallergenic. And boswellia, curcumin, and help oil to manage the headaches and nausea.
Hang in there, hope you get some relief soon.