I’ve had a histamine intolerance for a few years with worsening symptoms, cut out gluten and got on a low histamine diet which helped a lot at first. The hives came back a few months ago after briefly reincorporating gluten into my diet. I believe my intolerance for gluten was making me deficient in a lot of things, my medications were also not as effective when eating gluten. I was supplementing methyl b12, D3/K2, iron, C, and getting plenty of nutrients in through whole foods but it just didn’t seem to be helping anymore.

I cut out gluten again and at one point I tried to supplement methylfolate and it made me feel insane. Anxious, jittery, etc. I guess that should’ve been my sign that I could be deficient in folate, but instead I just stopped taking it. About 2 months ago I started supplementing folinic acid because I read it was much gentler on your nervous system and since then I’ve hardly broken out in any hives at all. I used to break out in hives from the temperature change of stepping out of the shower, a sharp wind on my skin, and skin irritation of any kind. That all has seemingly resolved in a matter of weeks.

Has anyone else improved after consistently supplementing folate?

I’m trying to figure out whether I’m dealing with a histamine flare or if I’ve actually picked up a virus, and I’d love to hear if anyone has experienced something similar.

I have histamine issues and normally take Pepcid daily along with Zyrtec. I was traveling this past week and completely forgot to take my Pepcid, so I ended up going about 5 days without it.

Now I’ve developed:
Sore throat (it hurts to swallow)
Lots of postnasal drip/throat clearing
A cough that’s mostly from trying to clear my throat
What feels like GERD/silent reflux

I know histamine can contribute to both postnasal drip and reflux, but these symptoms also feel enough like a regular cold that I’m second-guessing myself. I restarted my Pepcid today, but it’s too early to tell if it’s helping.

Has anyone here had a histamine flare that completely masqueraded as a viral illness? Especially with symptoms like postnasal drip, GERD, sore throat, or feeling like you’re coming down with something?

And the biggest question: What actually helped you?

Did anyone else here develop histamine intolerance suddenly in perimenopause? I have had mild-moderate outdoor allergies only since my 20s but NO issues with foods. Now almost everything I eat gives me a headache, sometimes migraine level severity and it lasts for 36 hrs. The DAO is helping but I feel like it must have a hormonal basis and I really want to cure this. I’m seeing things online about estrogen dominance messing with mast cells but I was told that I had progesterone causing headaches because it’s taxing my liver. I’ve been off the progesterone for a week and the headaches are the same. The only thing that helps at all is the DAO.

I have a severe copper deficiency, but unfortunately, I don't tolerate copper supplements.

So, my only option is to increase my copper intake through food.

Does anxiety increase histamines? I’ve found recently when we’ve ordered new furniture (sofa, bed, bedding) I’m having palpitations, dizziness and fuzzy feeling all over my body and can’t breath. With this I’ve been SO anxious. Even the thought of going near any new item makes me have the same sensation…

to those who replaced vegetable oil with animal fat how do you feel now with the symptoms

Every time I go to the doctor/specialist, I feel gaslit (I know it’s not all doctors but it’s the ones that I’ve seen) which is a lot of why I’ve put a lot of effort into figuring things out on on my own.

I’m just curious if doctors ever look at these Reddit threads that confirm all these people with the same symptoms? I know that Reddit is not a medical journal but this is just something I’ve been wondering.

Hi! I recently had a horrible flare up of my chronic gastritis. This was on June 26th I woke up with the WORST heartburn I have in a while due to some prenatals. I have had chronic gastritis for about 4 years now and I was feeling fine up until that day. I had horrible heartburn and nausea I could barely eat for the next 3 days so my doctor prescribed 20mg Omeprazole once in the morning only. On day 1 I developed tachycardia which it’s happened before so I brushed it off. On day 2 I was feeling off balanced a bit and kind of floating and towards night time I got super itchy on my outer thighs. I took it for an entire week where I began to realize I was getting random itchy spots throughout my body. So my doctor prescribed 40mg pantoprazole once in the morning instead. My itching snowballed after that. I began getting super itchy everywhere and developed dermatographia and the wheals lasted 10-15 min after I scratched. I kept taking it for about 2 more weeks because my heartburn disappeared and I felt like I was choosing between heartburn and itchiness and the heartburn was pretty much the worse option for me until I could see my Dr lol. Well, I was advised to stop the pantoprazole so my final day taking it was this Monday morning. It’s now Wednesday and I’m still itching, I was fine until I ate some oatmeal I prepared last night with blueberries and walnuts. Does this sound like a histamine intolerance? Could PPIs trigger this reaction? I feel so much itchier at night or after showers like a crawling stinging itchiness. If anyone can offer me some advice I’d greatly appreciate it. Thank you!

I have a severe copper deficiency—0.66 mg/L (normal is 0.85–1.05).

No matter the form of copper, my levels don't rise, and I start feeling anxious and getting a migraine-like sensation.

Has anyone here ever had this problem and managed to solve it?

I never used to drink coke or any other fizzy drinks. But I was desperate for some form of caffeine (coffee gives me horrible symptoms) and something sweet, so I was prepared to deal with the suffering after drinking coke.

From time to time, I cheat on my horrid diet because I have no energy and I still have some symptoms even while following a strict low histamine diet.

Anyway, I had no symptoms after drinking Coca Cola zero. In fact, I actually felt more relaxed, almost like it helped. I don't know if I'm imagining it, but my pulse stayed stable and I didn't even have reflux (I'm diagnosed with silent GERD/LPR).

What is happening??? I react to all kinds of healthy foods, including fruits and vegetables, even ones that are considered low histamine, yet I'm completely fine with coke zero. It actually feels calming. Why would that be? I usually react to almost everything, yet an unhealthy drink is making me feel better.

EDIT: I also forgot to mention that I let my coke zero go flat because carbonation makes me bloated and I've never liked fizzy drinks. Just to add some context and reply to a few comments: it doesn't make me feel "good". It just makes me feel... normal. Calm, like my body and mind aren't constantly overstimulated. It actually reminded me of how I felt before I developed histamine intolerance.

I'm already on antihistamines, DAO enzyme, supplements recommended by my allergist and a low histamine diet, but today is the first day my histamine intolerance has eased up a bit. I swear this should be studied lol. It doesn't feel like placebo, even the inflammation seems a little better.

Hey, I was just wondering if anyone else experiences this- do different foods cause different symptoms for anyone? For instance, having kimchi gives me terrible rhinitis and eye mucus under the eyelids very quickly after eating it, whereas take out pizza gives me less rhinitis but moreso terrible brain fog and fatigue for the rest of the day and especially the morning after.

If so whats the mechanism behind this? Or is it possible that I’m dealing with 2 separate issues here? I also get the same reaction I have to pizza with celcius (zero sugar energy drink), so I think that rules out blood sugar spikes.

I’m hoping this may help me to understand what has happened to me. Two years ago. I started taking a standard prenatal multivitamin with methyl folate amongst other normal vitamins. After two months I started getting a swollen face and histamine reactions to food and feeling not myself. Wired then tired. I was encouraged to continue by a gp as folate is important for fetal development. Eventually my RBC was through the roof well over double what it should be maximum. and I started having all kinds of awful symptoms. Numb hands at night. Horrific headaches going down my neck. Loss of balance. Sever histamine issues with food and fluctuating hormones. My skin turned to leather and my back was covered in deep spots. I also developed adenomyosis. Which for no issues my whole life seems very unusual. I am 41 for reference. I cannot seem to click the switch back off again. No matter what I try. I wonder if my liver has taken a massive hit but all my bloods come back normal. For some reason though my body wasn’t get rid of the excess. All my hormone bloods come back normal. But I am concerned I am now estrogen dominant and that is then driving more histamine and vice versa. And that in turn is causing this new adenomyosis diagnosis at such a late stage in life. I was considering milk thistle to help detox my liver. And dao to help with the gut?
I don’t think I have mcas. As I can lay in the sun all day. Wear perfume. Exercise with no issues. No skin issues. My main problems seem to be with food and hormones. My headaches are gone and no more loss of balance and skin back to normal. Sometimes my hands still go numb at night.

My significant methylation findings are:
COMT rs4680 AG and COMT rs4633 TC – associated with slower COMT activity
MTHFR A1298C – reduced function (my C677T is normal), so my issue is more related to BH4 production than major folate conversion.
Two CBS variants
Two GSS variants – suggesting reduced glutathione synthesis.
BHMT, CHDH and PEMT variants – suggesting a greater reliance on choline and betaine for methylation.

Any opinions or help would be greatly appreciated as I have tried everything. And now I am going towards ivf and these issues worry me that it will make it that much harder.

I'm trying to take histamine intolerance seriously, but a practical problem keeps coming up. I can eat a simple fresh meal like plain rice, chicken, and a low-histamine veg and be fine, but if I eat the exact same thing as leftovers the next day I get symptoms within an hour or two: flushed face, that wired-but-tired feeling, pressurey headache, and sometimes a weird tightness in my throat.

I work full time, so cooking every single meal from scratch is not realistic. I also have a history of GERD and bloating, so I try to keep things bland and consistent, but the leftovers problem keeps blowing up my plan.

Questions:

1) Is getting worse on leftovers a reliable sign of histamine building up, or could it be something else like food safety issues, fat oxidation, or just my stomach being irritated?

2) For people who are sensitive to leftovers, what actually helps in practice: freezing immediately after cooking, portioning into small containers, rapid cooling, only prepping ingredients instead of fully cooked meals, or something else?

3) If you freeze portions, do you notice a difference depending on how long the food sits in the fridge before you freeze it?

Not asking for medical advice, just looking for real-life tips so I stop wasting food and stop triggering myself every other day.

Must.... stop.... eating known trigger foods....

I swear I don't have amnesia. I think I just need to train myself to be strict even whilst being on a holiday.

I'm writing this one from both sides. I dealt with chronic pain and nerve symptoms for years before anyone connected it to B12, misdiagnosed, dismissed, told it was anxiety or just how my body was. Once my B12 actually crashed hard enough to force the issue, I started managing this myself through injections and a full protocol, because the healthcare system I was going through, WellStar specifically, still hasn't properly treated it despite lab results and symptoms that back it up. A lot of what "unexplained" pain and dysfunction I'd had for years started making sense once I did my own digging, even without the medical system actually stepping in.

The two enzyme systems that break down

B12 runs two critical reactions in your body. The first is methylmalonyl-CoA mutase, which converts methylmalonyl-CoA into succinyl-CoA; when B12 is low, this stalls and methylmalonic acid, MMA, builds up in your blood and tissues. The second is methionine synthase, which converts homocysteine back into methionine using B12 as a cofactor; when that stalls too, homocysteine builds up instead.

Both of these buildups are directly damaging to nerves. Elevated MMA disrupts lipid metabolism and mitochondrial energy production, and that instability undermines the myelin sheath, the insulation around your nerves. Homocysteine on its own is considered neurotoxic and is suspected of directly damaging nerve tissue, separate from whatever damage the MMA is doing. Two separate toxic pathways, converging on the same target, at the same time.

How one deficiency shows up as four different diagnoses

Chronic pain, fibromyalgia, CFS/ME, and MCAS get treated as four unrelated conditions, but B12 deficiency touches the exact biochemical pathways underneath all four of them at once. The myelin and mitochondrial damage from MMA and homocysteine explains the pain and fatigue. The same methylation cycle that's failing to clear homocysteine is also the one responsible for producing SAMe, and SAMe is the fuel for HNMT, one of your two main histamine clearing enzymes; when B12 is low, methylation slows down and histamine lingers longer than it should. That's the thread connecting a "nerve pain" diagnosis to a "mast cell" diagnosis to a "fatigue" diagnosis; it's one upstream shortage showing up in four different downstream systems depending on which tissue gets hit hardest.

Chronic pain specifically

Once myelin starts breaking down, nerves stop conducting signals cleanly. That shows up as burning, tingling, numbness, and pain, usually starting in hands and feet and creeping inward as it progresses. Left untreated long enough, this can progress into subacute combined degeneration of the spinal cord, simultaneous damage to the dorsal and lateral spinal columns causing loss of vibration sense, poor coordination, progressive weakness, and in advanced cases, paralysis. A neurology clinic study looked specifically at patients showing up with vague chronic pain that didn't match any clean nerve pattern, and a meaningful portion turned out to be B12 deficient, some as low as 19 pg/mL. A trial giving B12 for two weeks reduced chronic low back pain by 32 percent compared to placebo, and a 2020 systematic review found moderate evidence for B12 as a real treatment for neuropathic pain.

For me this showed up as chronic neck pain, body cramping, a sensation like a saw blade running through my brain when I bent my neck forward, and migraines. None of it read as a clean textbook pattern, so it kept getting written off.

Fibromyalgia specifically

Researchers looking at patients who met criteria for both fibromyalgia and chronic fatigue syndrome found that all of them had elevated homocysteine in their cerebrospinal fluid, even when blood levels looked completely normal. Their spinal fluid B12 was also low, and both correlated significantly with fatigue and mental fog, pointing to a problem with B12 transport across the blood brain barrier, meaning your blood test can look fine while your brain and spinal cord are functionally starved. A separate open label study gave fibromyalgia patients 1000mcg of oral B12 daily for fifty days and tracked pain, anxiety, and depression scores before and after, on the theory that the homocysteine buildup itself is what's driving oxidative neurotoxicity.

CFS/ME specifically

Same research above covers this directly, since the patients studied met criteria for both conditions together. The low spinal fluid B12 and elevated spinal fluid homocysteine correlated with the fatigue and cognitive symptoms that define ME/CFS, not just the pain side of fibromyalgia. That blood brain barrier transport issue is the key detail here; it means someone can be functionally B12 deficient in the one place it matters most for fatigue and brain fog while their standard labs look completely unremarkable.

MCAS specifically

Histamine gets cleared by two main enzymes, DAO in the gut and HNMT inside cells. HNMT depends entirely on SAMe as its methyl donor, and SAMe production depends on the same methylation cycle that B12 powers. When B12 is low, methylation slows, SAMe drops, and HNMT can't keep up, so histamine lingers and builds. B12 is also a cofactor that supports DAO function alongside B6, copper, and vitamin C, so a deficiency can weaken histamine clearance from both directions at once. This is why some people with MCAS or histamine intolerance notice real improvement once B12 status is corrected, and also why some sensitive people notice a temporary histamine-like reaction when they first start B12 supplementation, since it's shifting how much histamine is circulating rather than adding histamine directly.

Why this gets missed, and sometimes just ignored

Standard serum B12 tests are not reliable enough on their own. Neurological symptoms can show up even when serum B12 is technically within normal range, and there's no universally agreed cutoff that guarantees you're fine above it. This was true in my case too; my functional deficiency was real long before any standard test would have flagged it. MMA and homocysteine are functional markers, they tell you what's happening at the cellular level, and MMA specifically is one of the earliest and most specific indicators of intracellular B12 deficiency.

If you're on a PPI or metformin long term, you're vegetarian or vegan, you have any autoimmune or gut absorption issue, or you've had nitrous oxide exposure like I did, your risk is meaningfully higher, and a normal serum B12 result should not be the end of the conversation. Ask for MMA and homocysteine specifically, not just serum B12.

And sometimes it's not even missed, it's ignored. I've had labs and symptoms in hand that support this exact mechanism and still couldn't get WellStar to actually treat it properly. Part of why I write these posts is that a lot of us end up having to become our own case managers, because "the labs don't fit my checklist today" isn't the same thing as "you don't have a real deficiency."

https://omegaquant.com/neurological-symptoms-of-b12-deficiency/

https://biocrates.com/methylmalonic-acid/

https://emedicine.medscape.com/article/1152670-overview

https://www.ncbi.nlm.nih.gov/books/NBK441923/

https://www.b12-vitamin.com/nerves/

https://www.neurology.org/doi/10.1212/WNL.84.14_supplement.P3.307

https://www.dynamichealth.je/blog/vitamin-b12-for-nerve-health-and-chronic-pain/

https://link.springer.com/article/10.1186/s41927-022-00282-y

https://pubmed.ncbi.nlm.nih.gov/9310111/?dopt=Abstract

https://journals.plos.org/plosone/article?id=10.1371%2Fjournal.pone.0124648

https://biologyinsights.com/does-vitamin-b12-increase-histamine/

https://www.mthfrsupport.com.au/2016/09/dao-deficiency-and-histamine-the-unlikely-connection/

I get heart/chest pain and last night my face and eyes were swelling. If things were to progress so badly I was incapacitated, what would have to be done? I already told my mom if I'm in the hospital, to not let them give me saline because that will make it worse.

Will an epi-pen or whatever they do for allergic reactions save me?

I've already done everything I can but the symptoms have broken past all the medicine I've taken. I'm at the end here, I feel like there's about to be an emergency.

I am looking to purchase a DAO enzyme that will not trigger any histamine issues. I have seen the pea and pig kidney versions… I am not sure which is the best option.

Also, a DAO enzyme that doesn’t cause major reflux would be great too. I have reflux issues already.

If anyone has any recommendations, that would be great!

Are you guys good with cashews ?

So I was on a very strict low histamine diet for a while and it helped tremendously. But, when I stop doing the diet I feel fine but all of a sudden my symptoms will go from 0 to 100 over night. There is no clear food trigger and it’s impossible to identify my triggers because I get a delayed reaction that could take days to come out but when it does finally come out it’s AWFUL and completely debilitating. This diet is so incredibly hard and I don’t want to be stuck eating like this for the rest of my life in order to avoid flairs. Does anyone have any advice on how to figure out my trigger foods?

Looking into getting ancestral supplements to help with iron and fatigue issues.

I was wondering if anyone has experience taking beef spleen or liver capsules.

If so, did they cause histamine issues?

I have been iron deficient for a LONG TIME. I started supplementing iron for a while and developed EXTREME migraines, headaches, dizziness, vertigo, etc. I thought I had brain damage or MS.

Months later I have been playing around with different supplements and noticed after I ate ginger candies (which help with lowering histamine) some of my head pain resolved! However, ginger also caused me MAJOR acid reflux lol.

I was thinking I may have a histamine issue, but now I have no clue how to help it. I need to keep taking iron supplements, but they cause me such bad feelings in my head.

I am new to all these issues as I used to be perfectly healthy…

If anyone has ANY advice on anything I mentioned I would greatly appreciate the help. And yes, I have gone to doctors and they ignore my symptoms… 😭

I've just begun reintroducing foods again and would like to hear the best amount to reintroduce in your experience?

Last week I started with two gluten free weetbix, but I broke out in a rash, I believe I may have had too much to start with.

I had one tablespoon of cottage cheese yesterday, I experienced a little redness on my neck and eyelid, but it seems to be manageable for the moment, I will rest for day two and see how I am tomorrow for day three and possibly have another tablespoon to see if I can tolerate it?

Does anyone have any suggestions on how to go about the reintroductions?

I haven't managed to raise my copper levels for years, and I also react to copper supplementation with anxiety and migraines.

I’m now going to try Cu1 copper, such as "MitoSynergy" or "Global Healing Bio-Active Copper Supplement Cu1."

I’ve ordered it, but unfortunately, shipping to Germany will take up to a week or more.

Does anyone have experience with Cu1 copper, such as "MitoSynergy" or "Global Healing Bio-Active Copper Supplement Cu1"?

Had my own Kounis type episode triggered by honey, so I went digging into the actual research to understand why, and found some real mechanistic threads connecting honey, histamine, mast cells, and B12 deficiency, some documented directly, some I'm connecting myself.

What Kounis syndrome is

Kounis syndrome is an acute coronary event triggered by an allergic or hypersensitivity reaction rather than typical plaque buildup, first described by Kounis and Zavras in 1991. The mechanism runs through mast cells, when they degranulate during an allergic reaction they release histamine, tryptase, chymase, and leukotrienes, and these mediators directly cause coronary artery vasospasm and can provoke plaque rupture. Mast cells are concentrated between myocardial fibers, around blood vessels, and in arterial walls, so this isn't a distant systemic effect, it's happening locally in the heart tissue. It shows up clinically as chest pain, ECG changes that can mimic a heart attack, and elevated cardiac enzymes.

Honey as a documented trigger

There's a specific documented case of mad honey, made from nectar containing grayanotoxin, causing Kounis syndrome through mast cell activated vasospasm, confirmed on angiography as a type 2 MI. That's the only honey specific case report in the Kounis literature.

Regular honey isn't in a Kounis case report, but the histamine mechanism is separately well documented. Honey itself is generally low histamine as a food, but it carries pollen, and pollen proteins are classic IgE mediated allergens that cross-link IgE on mast cells and trigger degranulation. Honey also contains biogenic amines like putrescine and cadaverine, which trigger histamine release from mast cells and add to total histamine load even though they aren't histamine themselves.

Where B12 fits in

This is where it gets interesting. B12 plays a direct role in histamine clearance through the HNMT pathway, one source lays out the mechanism specifically, reduced methyl B12 activity means insufficient SAM available for the HNMT enzyme to methylate and break down histamine, so histamine released from food ends up causing symptoms that mimic mast cell activation even when the mast cells themselves aren't the primary problem. Other sources describe the same link from the other direction, B12 deficiency impairing DAO activity and reducing methylation capacity broadly, both of which are needed to clear histamine effectively. MCAS is also specifically noted as often associated with functional B12 deficiency in the literature.

Putting it together, my own connection, not an established finding

None of these sources actually link B12 deficiency, honey, and Kounis syndrome together in one study, so this next part is me connecting three separate bodies of research based on my own case, not citing something already proven. My working theory is that in someone who is B12 deficient, histamine clearance through HNMT and DAO is already impaired, so the histamine and biogenic amine load from honey doesn't get cleared efficiently, mast cells release their full mediator cocktail, and in a heart that's already sensitive, that mediator surge is what triggers the coronary vasospasm underlying a Kounis event. Whether that connection has been studied directly, I don't know, I haven't found it in the literature yet, but the individual pieces (B12 deficiency impairing histamine clearance, honey triggering mast cell degranulation via pollen and biogenic amines, and mast cell mediators driving Kounis syndrome) are each independently documented, they just haven't been strung together as one pathway in a published case as far as I can find.

Kounis syndrome mechanism and mast cell pathway, PMC6614985, https://ncbi.nlm.nih.gov/pmc/articles/PMC6614985

Mad honey induced Kounis syndrome case report, International Journal of Cardiovascular Academy, https://ijcva.org

Kounis syndrome review, PMC12597132, https://pmc.ncbi.nlm.nih.gov/articles/PMC12597132

Honey histamine and pollen allergen content, Fact vs Fitness, https://factvsfitness.com/en-au/blogs/news/honey-high-histamine

Honey and histamine intolerance mechanism, Wyndly, https://wyndly.com/blogs/learn/honey-histamines

B12, SAM, and HNMT histamine methylation mechanism, https://b12oils.com/mcas.htm

B12 deficiency, DAO, and methylation in histamine intolerance, Dr Hagmeyer, https://drhagmeyer.com/vitamin-b12-and-histamine-intolerance-everthing-you-want-to-know