In December, one of my doctors (Dr. M) gave me a diagnosis of Mast Cell Activation Syndrome. I wasn't entirely confident about the diagnosis, but am willing to try various recommended treatments. Dr. M first recommended that I try successive two week trials of each of the four major brands of over-the-counter H1 blocker allergy medications. (I don't want to write the brand names in this post, but they are well known.) I tried all four and didn't notice a significant difference with any of them.
Dr. M had recommended that if the 1-dose per day regimen didn't work, that I should try up to 3 doses per day. I never tried that because I'm hesitant to exceed the box's indications. Perhaps in the future if I read about other MCAS patients having success with larger doses, I may try it, but I haven't yet sought out recommendations from other MCAS patients. My doctor also wrote a prescription for cromolyn liquid, 100mg 4x/day, in the event that the over-the-counter options failed.
In the meantime, after being in more-or-less remission from SIBO for about 4 months in late-2018 and early-2019, the symptoms started to return in March. (My SIBO symptoms are feeling of intense inflammation and bloating throughout the gut, accompanied by constipation—I have the methane-based type of SIBO.) As you can imagine, this was a disappointment for me. By mid-May, the symptoms were as bad as they have ever been.
When the SIBO symptoms reached a peak in late May, I decided to fill the cromolyn prescription on the chance that it helped with the SIBO symptoms. It certainly seemed to help. Almost immediately after I began taking the cromolyn, my gut symptoms improved. (As I found out later, there is a connection between SIBO and MCAS, so it might make sense that cromolyn would help SIBO symptoms. For example, this link.)
My experience with SIBO has been a wild ride and the symptoms have waxed and waned at times without any explanation, so it's difficult to know with certainty if the cromolyn was the reason for the improvement. I also still experience some SIBO symptoms, but not as bad as in May. Also, my dose of cromolyn is half of what other patients report taking. I may need to increase the dose to further experiment—if insurance will cover it.
In the meantime, I've started the process of seeking insurance approval for intramuscular IgG, which should help with SIBO as well as continued positive IgM for Epstein Bar Virus and other issues. The insurance company (of course) rejected the first effort for approval. They want me to undergo a further antibody production test which would involve receiving vaccinations for diphtheria and tetanus and then subsequently testing whether my body's antibody response is sufficient. I have many reservations about this but I am considering it.
Edit: "H2 blocker" replaced with "H1 blocker."