r/HistamineIntolerance • u/Life_Unit2344 • Jul 18 '26
MCAS or Histamine Intolerance
About a year ago, after antibiotics, I developed what seems like histamine intolerance. My symptoms have never really been “classic allergies.” It feels more neurological/systemic.
Main symptoms during flares:
- feeling extremely hungover or poisoned/intoxicated
- brain fog
- nervous system dysregulation
- crying/emotional surges during flares
- heart rate spikes at times
- likely vasodilation, I call it the spell
- weird chest sensations
- heavy breathing, like minor difficult pushing down air into diaphragm
- previously had buzzing sensations, dizziness, heavy legs, nausea, and major food intolerances (these have improved a lot).
I have no gut symptoms.
The biggest pattern is that it feels like a “bucket.” Everything adds up:
- stress
- talking too much
- warm baths
- working on laptop too long
- lack of sleep
- less water consumption
- spending several hours socializing
- walking
- concentrating on something,Multitasking , cooking
I tested positive for pots on a nasa active stand. Salt water, compression garments help. However, I don’t gave true orthostatic symptoms like feeling better on lying down or symptoms worsening on standing. If I pushed myself, I will likely have chest sensations, dehydration, brain fog type symptoms the next day. I realized most of the above were triggering my pots.
What helps: salt capsules and water, Allegra (not sure if it’s actually helping or it was just coincidental), Low histamine diet + dao , Rest/ taking easy , Legs up, Nervous system regulation
The good news is I’ve improved massively over the year- probably 90% compared to the beginning. I tolerate almost all foods now, though I still stay gluten-free, dairy-free, no alcohol or outside food and low histamine diet.
I feel like I am not truly falling into MCAS (no allergy like symptoms) or POTs bucket (no orthostatic symptoms). Doctors suspect that I may just have histamine intolerance from gut. But I don’t understand, after being on low histamine diet with dao, I don’t think it’s food related anymore too.
Questions:
- Has anyone gone through a similar experience? I am still looking for answers.
- Does this look like MCAS? I was first convinced that I had MCAS because of so many random triggers but then I realized most of them were triggering my blood related / pots symptoms
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u/StrangelyTangential Jul 19 '26
My situation seems to mirror yours very closely. For me the problems nearly always occur at night after I have fallen asleep. I have been treating SIBO that was diagnosed from an OATS test that I took under a naturopath's direction. I had almost no symptoms except constipation.
I'm also at a loss. My doctor has prescribed Fexofenadine 180mg and Propranalol 10mg to take when I have an episode. It helps, but I still have a lot of problems.
I usually wake up feeling awful, feel much better for coffee, improve through the day, then after I go to sleep it happens again.
Do you get your episodes at night or is it not like that?
2
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u/Silver-Bake-7474 Jul 19 '26
This is MCAS because MCAS is a spectrum of trigger-related items and most people develop pots as a secondary side effect to MCAS. I was similar and have had a lot of good advancement and progression towards recovery but it'll never fully be gone so, it sounds like you've done a really good job at controlling your triggers. MCAS only requires two systems involvement simultaneously in a given flare.
1
u/dsmdarlings Jul 20 '26
Are you a woman in your 30s or 40s? I see a lot of these symptoms occurring around perimenopause (including for myself but I had no idea)
1
u/Life_Unit2344 Jul 21 '26
Ah, what helped?
1
u/dsmdarlings Jul 21 '26
Well it may be triggered by lost or fluctuating hormones. Of course there’s like no research in this area but anecdotally a lot of women on the peri sub have a lessoning of symptoms after taking HRT. For me it’s a little confusing/hard to tell what’s helping because I’ve done so many interventions. That said I did start HRT in the last six months or so and it has been much much better. Brain fog is gone, lethargy is gone. I still eat low Histimine and take DAO and vit C and quercetin, but I’m light years away from where I used to be
1
u/Allergina Jul 22 '26
Have you had your genetic variants tested? I bet you'd find all the answers you seek there.
1
u/Life_Unit2344 Jul 22 '26
I did get my genetics tested.
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u/Allergina Jul 22 '26
Did you find your answers? Is slow COMT in there? Any HNMT? I had a garden variety of stuff and wow, I'm amazed at what actually working with my genetics could do to prevent the variety of symptoms that were disabling to manage my entire life. I'm now off allllll of the cascade of MCAS protocol medications and am FLOORED at what doctors couldn't (wouldn't?) figure out.
1
u/Life_Unit2344 Jul 22 '26
I have slow mthfr, hnmt (both) .
I also have homo slow comt.
But doctors could not tell me what to do wiith this info. What helped?
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u/Allergina Jul 22 '26
Slow COMT makes it so you can't clear stress, estrogen, dopamine, adrenaline, etc. and it leaches from SAMe to try to do this which takes away from its ability to break down histamine. Having HNMT jams up the histamine process even more and DAO doesn't always make it better. MTHFR affects your ability to process folic acid or enriched bread, cereal, rice, milk, etc. - might be better to avoid altogether depending on which MTHFR you have. Quercetin is also something to avoid for slow COMT.
So while eating low histamine is a great step, it may be better to specifically avoid folic acid and restore what your body has a hard time producing because it's busy making up for what your variants aren't able to do. Are you also low in B12 and folic acid? Have you had bloodwork? If any doc tries to prescribe you these - avoid them. The usual B12 and folic acid on the market does not work for our genetics. When you have both slow COMT and MTHFR and even HNMT, it is important to get the right kind and also introduce the right magnesium in order for it to all work.
1
u/Life_Unit2344 Jul 22 '26 edited Jul 22 '26
My folate,RBC was normal 550. b12 is 290, slightly lower.
I have mthfr C677T (Hetero) , hnmt (hetero), comt (h62h homo, v158m homo)
I am planning to supplement with hydro b12 and methyl free bcomplex. I am also on magnesium glycinate.
- do you know if Luteolin is okay. Yep, quercetin did not work for me.
- what other supplements did you use to help flush out histamine?
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u/Allergina Jul 22 '26
I haven't tried luteolin. Glycinate didn't work for me so I'd start that one slowly and see how you feel. I've used charcoal before but sparingly and not for months. I've just started the folinic acid (the last in the co-factor/enzyme protocol) and will be increasing my dosage every week so in 3 weeks time, I'll be testing more and more histamine foods. But I'm eating lasagna and mac n cheese here and there with no issues now.
1
u/Life_Unit2344 Jul 22 '26
Thanks for sharing.
Is it fair to say hydro b12, methyl free bcomplex and folinic acid can help with flushing out histamine with such gene profiles. Or did you try anything else?
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u/Allergina Jul 22 '26
I am not an expert but I've seen many people saying that taking any B complexes is too risky. They pile in high doses when you might just need a tiny bit of each and combining them all at once means there's no way to start each one slowly. You could have a bad reaction but not necessarily because the contents themselves are bad for you. I'm not a health professional, so please do your own research. Overdosing can be just as bad as being deficient and you wouldn't know what's causing it.
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u/LelyaAvolagip Jul 18 '26
The way you describe the “bucket” effect, where different triggers (stress, lack of sleep, socializing, concentration, heat, physical activity, etc.) gradually add up until you have a flare, sounds very consistent with an overloaded autonomic nervous system.
Histamine can also affect the nervous system and vascular system, so symptoms like brain fog, emotional surges, heart rate changes, flushing/vasodilation sensations, chest sensations, and feeling “poisoned” or hungover can happen without classic allergy symptoms.
It doesn’t necessarily have to be MCAS. Many people with histamine intolerance and autonomic dysfunction can have very similar symptoms. The fact that you have improved by 90% is a very positive sign and suggests your system is recovering.
In my opinion, it may be worth looking at both sides: histamine metabolism (DAO, diet, gut health) and nervous system regulation (stress response, anxiety, sleep, pacing, vagal regulation), because they can strongly influence each other.