Mast Cell Activation Syndrome: The Hidden Trigger Behind Food Reactions, Fatigue & Chronic Symptoms | E181
25 Sept 2026 · 8 min
Dr. Aaron Hartman explains mast cell activation syndrome, a condition that mimics Lyme disease and chronic fatigue by triggering hives, food sensitivities, brain fog, and fatigue. He describes two diagnostic approaches and practical treatments like antihistamines and mast cell stabilizers, plus how to identify triggers from stress to mold to COVID.
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And if you have mast cell activation syndrome, sometimes you have to start with it, not with the mold and not with the Lyme or otherwise, because your symptoms are so bad. But ultimately, wherever the trigger is, and that's where it gets tricky with mast cell activation syndrome, rewinding back, when did it start? Started after my concussion, started after I went to college. Some people, it starts after they start their cycles or they go through menopause. And so all of a sudden, is there a hormonal component to this? Why are you stuck? Why are you going from provider to provider? People are giving you some answers, but not the right answers. You might get a little better, a little worse, but you're still stuck. Why are you still sick? Some of these concepts I do recommend people consider reading, um, Dr. Um, Neil Nathan's book Toxic. And he has a new book out as well about, um, healing, treating the sensitive patient. Because he'll talk about a lot of these in the books. If you want to take a deeper dive, we've interviewed him on the podcast. You can look at those interviews, you get his book, because these are all great resources. His book is also on our reading list on the website. But the next topic discussed in that book and discussed other places is mast cell activation syndrome. Mast cell activation syndrome is interesting because the mast cell is like, many of you may or may not have heard of this. Well, let me start. What kind of symptoms can you have with mast cell activation syndrome? Usually you have, you can have skin symptoms, rashes, hives, sensitivities, reactions. You react with foods, chemicals, supplements. You might have palpitations, fast heart beating. You might have GI issues, problems. Diarrhea, constipation, brain fog, fatigue. It's really interesting if you look at the symptoms of chronic fatigue and fibro, of Lyme, of mold, where they all cross over. There's about 80% similarity with the different symptoms. And mast cell is like the thing that kind of connects all those because it's part of the immune system that lines organs, lines empty spaces like your bladder, colon. It is also along arteries and nerves. So all of a sudden you can have lots of different symptoms like interstitial cystitis, right? You can have other things, neurological issues. And part of the strangeness of Lyme disease is the mast cell component that can give you a lot of weird symptoms. One thing about mast cell activation syndrome that's interesting is you can start treating people's symptoms and helping them feel better without actually treating the underlying cause, which can be huge because some of my individual— individuals I work with are so sick they can't tolerate anything. They can't tolerate food. It's almost like they're eating like lamb and apples and water or whatever. And calming the mast cells down can help calm the nervous system down. Every fall, the schedule tightens and most of our attention goes to getting the kids ready. Almost none of it goes to the person holding the whole thing together. So I put together these 3 things just for that: a daily multivitamin in the active forms your body can actually use, quercetin and nettles to support your immune and respiratory health without the drowsiness, and NAC and acetylcysteine to help your body rebuild its own antioxidant reserve. This is what I take every fall. That's aaronhartmanmd.com/backtoschool. Now, there's some debate. There's a consensus criteria 1 and consensus criteria 2. And basically, one consensus criteria is based on the worst, the worst, the worst in the university settings where you actually have an abnormality in your mast cell number, not their function. So, if you do a lab test, you'll see the numbers are crazy sky-high. And, that's more mast cell disease. And, that diagnosis has been appropriated and called mast cell activation syndrome. In this one particular criteria. And if you go look out, you might see this. The second consensus criteria is one used by most people in the mast cell activation syndrome world. Dr. Afrin, that whole world, which is getting bigger and bigger and bigger, use the other consensus criteria, which is based on, you know, some labs, but it's mainly a diagnosis, a clinical diagnosis as well. Why is that? The reason why is because the lab testing are fleeting. If you do a histamine, a prostaglandin D2, you do a tryptase level, all these things Last a minute or 2 or 3 in your body and they're gone, maybe 5 minutes. And if your blood's drawn and sits on the countertop for 20 minutes before it's processed, your urine sits out unrefrigerated. These meteors can disappear and all of a sudden the diagnosis is missed. In our office, we actually have chilled tubes. We have chilled containers that we process them. We're keeping them cool. We're processing them there and freezing them on site, not sitting around. Even then, it's still not quite enough. You have to have a cold centrifuge, which we don't have, because that's like a typically a research-based or big lab-based thing. It gets hard sometimes to get the lab tests done, right? So then you use the clinical criteria. And ultimately, a lot of things you do in the clinical world, on the research world, as well as the legal world, is exposure, reaction, exposure, reaction, exposure, reaction, or treatment, reaction, treatment, reaction, treatment, reaction 3 times. And that makes something statistically significant in the 95% confidence interval. I know Big words for sciencey words. But the idea is that if you say take Pepcid, Zyrtec, Zantac, you know, whatever, and your symptoms get better, luteolin, rupatadine, you know, whatever your mast cell combination is, you get better. Stop them, you get worse. If you do that 3 times, that actually statistically, that meets statistical significance. So when people talk about what's your data, what's your research and what's the article, et cetera, et cetera. I'm like, well, I did a self-initiation trial that reached the 9/5 confidence interval. You know, that's what that is. Every fall, the schedule tightens, and most of our attention goes to getting the kids ready. Almost none of it goes to the person holding the whole thing together. So I put together these three things just for that: a daily multivitamin in the active forms your body can actually use, quercetin and nettles to support your immune and respiratory health without the drowsiness, and NAC and acetylcysteine to help your body rebuild its own. Antioxidant Reserve. This is what I take every fall. That's aaronhartmanmd.com/backtoschool. And so, it's used a lot to actually— that's how with mold, for example, mold reactions in the legal world when you try to prove someone's building and you're doing a deposition, a case like that, 3 times thing is what's used in the court of law to prove mold is related to your illness. So, with mast cell, we kind of use those principles and then use treatment trials. But mast cell can look like a lot of different things. And it's interesting because it's part of your immune system being activated by a trigger. The trigger could be stress. It could be your nervous system. It could be a food, external chemical. You know, some patients, it's walking down the aisle at, you know, Costco where all the perfumes and cleaning stuff is, going through Bed Bath& Beyond with all the chemical scents. Some people, it could be reactivation of your Lyme or a mold exposure. And part of the mast cell thing is removing the trigger, which gets tricky if the trigger is mold Or the trigger is Lyme, or the trigger is your SIBO, or the trigger is something else, then you also have to have that expertise to start dealing with those things as well. But the idea is that mast cell activation syndrome, it falls into the great imitator, you know, categories. And if you have mast cell activation syndrome, sometimes you have to start with it, not with the mold and not with the Lyme or otherwise, because your symptoms are so bad. But ultimately, wherever the trigger is, and that's where it gets tricky with mast cell activation syndrome, rewinding back. And this is where the clinical expertise Working with someone who's a clinician who's been seeing lots of patients for years and years and years, you can look back at your past. When did it start? Started after my concussion, started after I went to college. Some people starts after they start their cycles or they go through menopause. And so all of a sudden, is there a hormonal component to this? It could start after traveling abroad and getting a— getting food poisoning, you know, lots of different things. After COVID, after the COVID vaccine, which I, you know, is now acceptable talk about now, but Um, those after a flu, lots of different things can actually trigger your immune system, your mast cells. And so mast cells are a little tricky because that requires a lot more therapeutic trials. The diagnosis in many ways, if you, if you think you have mast cell, if you think you have Lyme or mold, you really should look at all those because they tend to unfortunately come together. But that could be one of the reasons why you're stuck and your body's not healing. Anyway, I hope this information is helpful. And then we're going to talk about the next topic of why are you getting better? Why are you stuck? What else could be going on?
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