A primer on Mast Cell Activation Syndrome (MCAS)

June 27, 2023 4:50 AM

Mast Cell Activation Syndrome (MCAS) is an under-diagnosed health condition that can lead to odd symptoms. "Mast cells are a part of your immune system that are present in connective tissue (which is why the disorder is very often comorbid with Ehlers-Danlos...). They store histamine and heparin, and release them when encountering certain environmental conditions and allergens... MCAS happens when your mast cells are very bad at identifying environmental conditions and allergens they should freak out at, and instead they freak out ('degranulate') at literally [effing] everything..." Writer synecdochic discusses do-it-yourself ways to diagnose and treat MCAS, and recommends Mast Attack for more details.
posted by brainwane (4 comments total)

and a lot of doctors are judgy fucking dicks about new systemic disorders with highly individualized presentations and mostly found in women, because it's likely extremely underdiagnosed and that leads to doctors being judgy fucking dicks about "the new fad diagnosis"

That tracks, in my experience.
posted by AlSweigart at 7:10 AM on June 27, 2023 [9 favorites]

The article mentions that both POTS and MCAS, previously considered rare diseases and commonly comorbid with hypermobility syndromes, seem to be common sequelae of Covid infections. I read somewhere that pre-Covid, something like 1% of the population had POTS, and now it's more like 4%. (Citation needed, I can't immediately find the article).
I find that really interesting, and I'd like to think that might lead to them getting more attention and better treatment, but I'm not holding my breath.
posted by BlueNorther at 9:16 AM on June 27, 2023 [1 favorite]

POTS, MCAS, Diabetes are all much higher risk post-COVID. I haven’t gone to get an official POTS diagnosis because I’ve kind of given up on a doctor being helpful (metafilter helped when a doctor commented in one of the last LC threads)… but standing up and being inexplicably dizzy with a 30+ bpm raise is pretty much my life now.
posted by OnTheLastCastle at 9:23 AM on June 27, 2023 [5 favorites]

Super interesting, looking forward to reading this. Immunology is so weird and the immune system is this delicately balanced dance that can become imbalanced in so many different way -- not fighting off diseases, or missing cancer cells, or creating autoimmune disease of various kinds... And how the immune system behaves is intimately intertwined with the microbial communities in your body, too.

I feel like our thinking on the immune system is currently shifting from the simplistic "body's defenses against pathogens / self vs. nonself" to the broader "body's system for diplomacy" to something even more subtle and complex.

Also wanted to reply to the above comments about POTS. From a paper in Feb. 2020:

"The prevalence of POTS is around 0.2% in the general population, and an estimated 500,000 to 1,000,000 individuals in the United States have the disorder."

U.S. defines a "rare disease" as one that affects less than 200,000 people in the U.S., so POTS doesn't quite qualify, but it wasn't exactly common pre-COVID either. I'm finding a lot of papers linking POTS to long COVID, but nothing (at least not after a quick search) giving a ballpark number on how much the incidence of the disease has increased.
posted by cnidaria at 8:35 AM on June 30, 2023 [2 favorites]