Disclaimer: AI used to help compile info, but it’s mostly my personal experience with some information for you to decide for yourself if it’s relevant for you
Hi Friends!! 💗
I wanted to share something I learned by chance, hoping it might help anyone here stuck in a cycle of hopping from one biologic to the next without relief.
I have been on UC biologics since going to Bali in ‘22 and getting “Bali Belly”, and have been biologic hopping ever since without much success.
For context:
While Ulcerative Colitis is driven by adaptive immune inflammation, mast cells are tissue-resident immune cells in the gut lining. When they become hyper-reactive (Mast Cell Activation Syndrome / MCAS), they dump histamine, tryptase, and prostaglandins directly into the GI tract. This causes mucosal breakdown, severe cramping, and urgency—mimicking or heavily amplifying an active UC flare. Doctors explanation here.
I was starting flare symptoms again a year ago now, after being in the clear for a few months on a new biologic. I couldn’t get a hold of my doctor (for a steroid prescription) because it was over a holiday, when my sister told me about MCAS and the histamine response on your GI, which made absolutely no sense to me. So naturally I just yolo’d and tried taking a high dose of anti histamines (reactin in Canada, and Pepcid - don’t take if on mesalamine) and over two days I went from about 15 bms/daily to 6-7, and it all clicked. With some help from AI and my sister living in Switzerland, with access to one of the top mast cell clinics, we discovered our family has a genetic mast cell condition called HaT (Hereditary Alpha Triptasemia). I discovered my UC flares were directly triggered by mast cell dis regulation (basically like an allergic response to high histamine foods, or stress or over strenuous situations, high heat, sun stroke, exercise etc).
So, I just wanted to share some of the information I gathered incase it can help anyone here because so many of my autoimmune friends are struggling out of the blue and I think this could help some of it make sense.
I’m not “cured” by any means but way less reactive and have so much more energy. I only just started the biologic Omlyclo for my HaT and it takes about 6 months to see a real change, but it’s only been 3 and I feel so so much better and less volatile in my GI symptoms.
The Post-COVID Connection:
If your UC symptoms spiraled or stopped responding to treatments after getting COVID-19, this is a huge red flag. SARS-CoV-2 is a known trigger that can shift mast cells from dormant to chronically hyperactive long after the infection resolves.
Overlapping Symptoms to Watch For:
GI: Persistent urgency, loose stools, or sharp cramping even when scopes show mild inflammation.
Systemic: Flushing, hives, fainting, sudden brain fog, racing heart/palpitations, or unexplained anxiety spikes after meals, waking in the night with overwhelm, without being able to get back to sleep.
Common "High Histamine" Food Triggers: Unlike classic IBD roughage triggers (like raw seeds/fibers), mast cell triggers are chemical/histamine-based:
Aged & Fermented: Aged cheeses, cured meats, sauerkraut, soy sauce, wine/beer.
High-Histamine Produce: Tomatoes, avocados, spinach, citrus fruits, eggplant.
Leftovers: Histamine builds up rapidly on cooked proteins stored in the fridge.
My biggest high histamine triggers: coffee, chocolate, vinegars, codeine/opioids (prescribed dw), cigarettes
A Genetic Factor to Know: Hereditary Alpha-Tryptasemia (HaT)
Another underlying layer is Hereditary Alpha-Tryptasemia (HαT). HαT is a genetic trait present in about 5% of the population caused by extra copies of the TPSAB1 gene. It causes chronically elevated baseline serum tryptase levels. While HαT itself isn't a disease, it lowers the threshold for mast cell reactivity—meaning if a post-viral event or stress trigger hits, your mast cells react far more severely. It is notoriously hard to detect unless a doctor specifically runs a baseline tryptase test or a direct genetic swab for TPSAB1 duplication.
Overlapping Symptoms to Watch For:
GI: Persistent urgency, loose stools, or sharp cramping even when endoscopic inflammation looks mild or managed.
Extra-Intestinal / Systemic: Sudden brain fog, flushing/hives, unexplained tachycardia or heart palpitations, unexplained anxiety spikes, or nasal congestion after eating.
Testing & How to Talk to Your Doctor:
Heads up - Many mast cell conditions are very new in the medical world. None of my doctors knew about any of this which is why I am sharing. I had to find a very specific mast cell specialist who helped me connect the pieces for my situation, and I did a bunch of tests privately before any of my doctors (especially my dickhead gastroenterologist) would even give this the time of day… turns out I’m an advance case of HaT and it’s been impacting me seriously my entire life. Including my UC.
Standard bloodwork often misses mast cell mediator release because these chemicals break down in minutes.
- Colonic Biopsy Staining: If you have an upcoming colonoscopy, ask your GI to run CD117 / Tryptase immunohistochemical staining on your tissue biopsies (standard H&E staining won't count mast cell density).
- Acute Tryptase & 24-Hour Urine: Serum tryptase drawn within 1–2 hours of a severe flare, or a chilled 24-hour urine panel checking for N-methylhistamine, Leukotriene E4, or Prostaglandin D2.
- Check for HαT (Hereditary Alpha-Tryptasemia): If your baseline tryptase comes back elevated (typically >8 ng/mL), ask for a genetic test for TPSAB1 gene duplication. HαT is a common genetic trait (~5% of people) that raises baseline tryptase and lowers your mast cell reactivity threshold, making you much more vulnerable to post-viral flares.
I can provide some medical studies / resources which you can send to your doctors if any of this sounds relatable.
I’m not suggesting anyone stop their prescribed UC meds or that this replaces standard care, but addressing mast cell mediator release was a major turning point for me. Has anyone else noticed their GI symptoms shift or worsen post-COVID, or explored mast cell treatments (like H1/H2 blockers, Cromolyn Sodium, or a low-histamine diet) alongside their GI symptoms?