Written and clinically reviewed by Bahee Van de Bor, RD, BCAPSc PGDipDiet, Specialist Paediatric Dietitian, former specialist dietitian at Great Ormond Street Hospital, with over 20 years of clinical experience in paediatric digestive health.
Why the rashes that come and go send parents to histamine, and where I would actually start
Quick answer
Histamine intolerance in children is a clinical concept rather than a confirmed diagnosis. A 2026 paediatric position statement found no validated test and no agreed treatment pathway. Your child’s tummy symptoms are different. Constipation, diarrhoea and functional tummy pain can each be named and worked on, so that is where I start. And if your child gets hives, a doctor should check them, whatever is happening with their tummy.
The rash that comes and goes
Your child came out in hives again.
Not every day. Not often enough to feel like an emergency.
There may be headaches too, or nausea, alongside tummy symptoms that have gone on for months.
So you looked for a thread running through it, and found histamine.
Then you found the food lists. Tomatoes out. Cheese out. Anything in the fridge more than a day, out.
The rash has usually faded by the time you get an appointment. So you photograph it and search, and the internet offers histamine for a symptom nobody has seen.
Does my child have a histamine intolerance?
Nobody can tell you yet.
There is no validated blood test for children and no agreed treatment pathway [1].
Symptoms attributed to histamine intolerance have been reported across several body systems [1, 2]:
- Gut. Bloating, abdominal pain, loose stools or diarrhoea, nausea
- Skin. Flushing, itching or hives
- Head. Headaches or dizziness
Now the important part. Those symptoms are not specific to histamine intolerance, and every one of them has other explanations a doctor would want to think about. That list is not a checklist for diagnosing anything at home [1, 3].
A 2026 position statement from Polish paediatric gastroenterology and allergology societies describes histamine intolerance as a clinical concept, not a fully established diagnosis. It is not UK guidance or a clinical guideline [1].
Assuming a child has a histamine intolerance is a big deal. So we should sort the obvious things first.
The constipation. The diarrhoea. The pain.
And importantly, children can have more than one condition.
That is why you should not start an exclusion diet without speaking to a healthcare professional.
What about food allergy?
That gets excluded first.
If your child breaks out in hives, speak to your doctor.
An allergy-focused clinical history can help assess or exclude IgE and non-IgE mediated food allergy [4].
An immediate allergy usually shows itself within about 2 hours of eating the food.
Non-IgE allergy is delayed, and can show itself through gut or skin symptoms up to around 3 days afterwards, which is why it is so much harder to spot [4].
Do not test a suspected food at home to find out [1].
Two things make that appointment more useful.
Photograph the rash while it is there.
And write down what your child ate, roughly how much, what happened and how long afterwards, because an allergy-focused history is built from all four.
What about tummy troubles?
You can assess and treat tummy symptoms while the histamine question stays open.
You do not have to wait for an answer about histamine before working on constipation, diarrhoea or abdominal pain.
Those are the symptoms making daily life hard, and they are the ones with an established approach [5].
When the main gut symptoms improve, look again at the rest.
Are the headaches still there?
Has the nausea changed?
That tells you and your child’s clinician whether the symptoms are moving together or need separate assessment.
It does not prove whether histamine is responsible.
It gives you a clearer picture while your child gets help for the symptoms you can act on now.
One thing to be clear about, because it is a reasonable assumption and I have no evidence for it.
Constipation is worth treating for your child’s comfort and their bowel symptoms.
There is no evidence that a sluggish bowel holds histamine in, or that getting things moving clears it out.
If that is where you are, with ongoing pain, constipation or loose stools and no clear plan, you can see how I work with families.
How common is histamine intolerance in children?
Nobody has a firm number.
One study followed 394 children with ongoing tummy pain. Thirty-one were suspected of having histamine intolerance.
Sixteen stayed on a histamine-free diet, and fourteen improved.
Seven agreed to the one test that could confirm it. One child had it confirmed [6].
Histamine intolerance is estimated to affect around 1% of adults. There is no figure for children [2].
A 2023 paper tested 51 children with tummy pain and reported histamine intolerance in 29. I would be cautious about that finding.
There was no comparison group, and all 51 children were labelled as having some form of food intolerance or malabsorption.
The histamine label rested on a DAO blood test.
The lead author declared speaking fees from the company that makes the test.
That does not make the findings wrong, but they need independent replication [7].
Put the two side by side.
One study confirmed it in a single child out of 394.
Another reports that more than half the children tested had it.
That is not a small difference of opinion, and the larger number comes from the weaker study.
If it is frustrating to read that the evidence is this unsettled, I understand.
It does not tell you what is happening to your child, and it does not tell you what to do tonight.
What it does tell you is that the histamine answer is not available yet, and that the tummy symptoms are.
What is the link between histamine intolerance and IBS?
Nobody has established one. There is a finding that makes the question worth asking, though, and it is why I take it seriously.
Histamine is a messenger your child’s body makes for ordinary jobs, including making stomach acid and communicating with nerves [8].
You know what it does in one place: a nettle sting, a mosquito bite or hay fever.
Mast cells store histamine in tissues, including the lining of the gut.
Some children with IBS have more mast cells there than expected [9, 10].
That is a real finding.
It is also only an observation.
Counting mast cells is not the same as measuring histamine, and it does not show that histamine is causing your child’s symptoms.
What it does suggest is that a sensitive gut can have its alarm system set louder than it should be.
That is a better explanation than the one most families arrive with, which is that their child has somehow developed ten new food intolerances in six months.
What is the histamine bucket?
The bucket is a model, not a measurement.
It comes from Dr Janice Joneja, a Canadian dietitian and immunologist [11].
Histamine may come from food, but the model also includes inflammation, infection, allergy and stress.
Nobody can measure how full your child’s bucket is.
The model cannot tell you whether food explains a rash, but it can help explain why symptoms may vary from day to day.
In clinic, what adds to the load is rarely the fridge. More often it is stress, or a recent illness.
Should I try a low histamine diet for my child?
Not as a first step. But not never either, and this is where I part company with simply reading you the evidence.
For me it comes down to how much your child is suffering.
If we have worked on the gut properly and your child is still miserable, still missing school, still getting symptoms that come and go with no pattern anyone can find, then two weeks is a short time.
Short enough that the cost of trying it is small set against what you are already living with.
So yes, in that child, I would consider a trial of 10 to 14 days.
With a paediatric dietitian, for a defined period, with every food brought back afterwards.
Not a food list off the internet, and not open-ended.
Three things would stop me.
- Your child has not had the gut properly assessed and treated yet. That comes first, every time
- Another cause has not been ruled out. Allergy in particular
- Your child is already anxious about eating, or already on a narrow diet. The risk is different in that child, and it is not worth it
That last one matters more than parents expect.
Taking food away from a growing child can reduce calcium, iron, vitamin D, omega 3, B vitamins, protein and fibre [1].
The Rome V criteria for paediatric feeding disorders note that restriction meant to improve gut symptoms can itself feed anxiety around meals, including when it started with something read online [12].
That is not every child, and worry about a few foods is not a disorder.
But in a child who is already frightened of their tummy, a fortnight of removing foods can cost more than it gains.
There is also no validated way to bring foods back, which is the other reason this needs a clinician rather than a list [1].
Most families I meet have already taken something out before they get to me. The more useful question is usually not what to remove, but what the pattern is telling us. That is what the first phase of the Happy Belly Club® is for.
Can a blood test tell us?
No.
You may be offered a DAO blood test, named after the enzyme that breaks histamine down. A diagnosis in children should not rest on it [1].
In the Austrian study, DAO levels did not correlate significantly with the children’s measured histamine.
Repeat readings in the same child varied, sometimes crossing the cut-off [6].
Low DAO can also occur in coeliac disease and after gastroenteritis, so the number does not tell you which condition is present [2].
Most of the 31 children did have raised histamine measured in blood or urine.
Something was going on, but the study could not show that DAO identified it or predicted reactions during testing [6].
Those authors concluded that these blood tests may not be worthwhile in children.
On the supervised histamine challenge, their judgement was that “the risks and burden of this procedure outweigh the potential benefits in children” [6].
So no validated blood test can confirm this in children.
Which foods actually contain histamine?
Histamine can collect in food that has been aged, fermented or stored badly, as bacteria make it over time [1, 8].
Food is one possible source. These examples are not a list to start cutting:
- Aged cheese. Published figures vary widely. Fresher cheeses and fresh milk are at the low end
- Oily fish. Levels depend on how quickly the fish was chilled after it was caught, so handling matters more than the species
- Cured and processed meats. Curing takes time, and time is what lets histamine build
- Certain fermented foods. Fermentation is bacteria working on food over time, which is exactly how histamine forms. It does not apply to all of them
- Leftovers. Histamine can build in cooked meat and fish kept too long. This is a reason for ordinary food safety, not avoiding leftovers
- Alcohol. Not relevant for a six-year-old, but worth knowing if there is a teenager in the house
Aubergine, spinach and tomato are the plant foods most often named, and the ones you might be tempted to cut first.
But they sit far below aged and fermented foods, and there is no established threshold or reliable link between a food’s histamine content and symptoms.
One review took ten published low histamine diets and compared every food they exclude against its measured histamine content. Only 32% of the exclusions could be justified [13].
Online lists also name “histamine liberators”, foods said to release the body’s histamine. These are not supported as clinically relevant triggers [1].
What about antihistamines?
Ask your child’s doctor.
If your child is already using antihistamines regularly to manage rashes, please discuss that with whoever prescribes them.
There are no data confirming that antihistamines treat histamine intolerance in children.
The position statement says short-term, as-needed use may be considered for symptom relief, and stopped if it does not help [1].
I am a dietitian, so prescribing is not mine to do, and nothing here is a suggestion to start, stop or change any medicine.
What if we have already taken foods out?
Do not simply carry on because the diet seems to help.
The position statement recommends reviewing restriction, beginning reintroduction within about six weeks, and keeping out long term only foods that consistently provoke symptoms [1].
A planned reintroduction helps identify which foods, if any, your child reacts to.
Staying on the diet indefinitely never answers that question.
If your child is already avoiding several foods, ask your clinician or dietitian to review their growth, nutritional intake and how eating is affecting them.
Bringing foods back needs a plan, and that is not something to work out alone. A Discovery Call is a short conversation to work out whether the Happy Belly Club® is the right next step. It is not an assessment, and there is nothing to prepare.
Book your free 15-minute Discovery CallWhat about MCAS?
MCAS is a recognised condition in which mast cells release their contents too readily, causing symptoms in more than one body system [1].
Specialists, usually in allergy, immunology or haematology, diagnose it. A diet cannot diagnose MCAS, and it is outside my area. If you have read about it and think it might fit your child, ask your GP about referral.
What is safe to do if I am worried?
None of this means taking a food group away from your child.
- Change how you store food, not what you eat. Histamine is not destroyed by cooking or freezing, so once it has formed it stays. Freshness and storage matter more than cooking, and leftovers are better frozen than left in the fridge [1, 8]
- In practice. Cook fresh where you can. Cool cooked meat and fish quickly. Freeze what you will not eat within a day or two. Buy fish fresh or frozen at sea
- Consider one food, not a list. Occasionally I meet a child eating a lot of one high histamine food, usually cured or processed meat. Stopping that single food may be reasonable
- Keep the fruit and vegetables in. They go first and are least likely to be the problem
- Do not buy a DAO supplement. No study has evaluated its safety or efficacy in children, and it is not currently recommended for them [1]
- Histamine is not a reason to stop a probiotic that is helping. You may have read that certain strains make histamine. That comes from laboratory studies of bacteria in culture [14], and no study in adults or children has shown that taking one of them makes symptoms worse. If your child’s probiotic is helping their bowels, keep it. If you are not sure which one they are on, ask your dietitian
- Keep any diary short. Three to seven days, including a weekend day. A diary kept for months can make a family watch food harder rather than understand it better
These steps can limit extra histamine forming in food, and some children improve on them alone.
They do not assess ongoing constipation, diarrhoea or pain.
If those symptoms continue after a few weeks, they deserve attention in their own right, rather than a tighter food list.
Then look at what may be driving them, which for many children I see means working on the gut.
If that does not help, and symptoms outside the gut remain unexplained, raise the wider histamine question with a clinician.
When should I get help?
Call 999 now
NHS advice is to call 999 if your child [15]:
- Has sudden swelling of the lips, mouth, throat or tongue
- Is breathing very fast or struggling to breathe
- Has a tight throat, or is struggling to swallow
- Has skin, tongue or lips turning blue, grey or pale. On brown or black skin this can be easier to see on the palms or the soles of the feet
- Suddenly becomes very confused, drowsy or dizzy
- Faints and cannot be woken
- Is limp, floppy, or not responding as they normally do
Then, in this order:
- If your child has an adrenaline auto-injector, use it
- Call 999 and say you think this is an anaphylactic reaction
- Lie your child down with their legs raised. If breathing is hard, raise their shoulders or sit them up slowly
- If symptoms have not improved after five minutes, use a second auto-injector
Do not let them stand or walk at any point, even if they seem to be improving.
Speak to your GP soon
For the allergy question above.
Speak to your GP about the gut symptoms
If your child is losing weight or not growing as expected, has blood in the stool, wakes at night with symptoms, or has been told everything is normal but nothing has improved.
A clinician will consider other explanations, including allergy, coeliac disease and inflammatory bowel disease, before any diet.
What does support through the Happy Belly Club look like?
We do not begin by removing more foods.
In my 12-week, 1-to-1 clinical programme, the Happy Belly Club®, I start by looking at your child’s gut history, growth, stool and symptom patterns, what they eat and drink, when flares happen, and what you have already tried.
In the Restore phase, I tailor recommendations and introduce them in a deliberate order. For most children, that means adjusting amounts and timings rather than removing food groups.
The Thrive phase helps maintain progress, broaden the diet and prepare you for the next flare. Over 12 weeks, I can see how your child responds and adjust as we go.
The aim is a child who eats comfortably and a diet as broad as it can be. I cannot promise you an outcome, and anyone who does should worry you.
If your child needs a doctor, particularly for suspected allergy, that assessment comes first.
The Discovery Call is a 15 minute conversation about whether the Happy Belly Club® is a suitable next step. We talk about what has been happening and what you have already tried, and I tell you honestly if it is not right for your child. The full clinical assessment happens after joining.
You can book a free 15 minute Discovery Call when you are ready.
Working through this properly
Tummy pain, constipation or loose stools that have gone on for months usually have a pattern behind them. Finding it takes a proper look rather than another food off the list. The Happy Belly Club® is my 12-week one-to-one programme for families in exactly this position.
See how the Happy Belly Club worksFrequently asked questions
Is histamine intolerance a real diagnosis in children?
Not yet. A 2026 paediatric position statement describes it as a clinical concept rather than a fully established diagnosis. There is no validated test for children and no agreed treatment pathway. That does not mean your child’s symptoms are not real. It means the label cannot be confirmed, so it is not the place I would start.
Should I deal with the constipation first, or the histamine?
If your child is constipated, that needs assessing and treating, and for most children I see it is where I start. But some symptoms need a doctor alongside it, not after it. Recurring hives, a reaction soon after eating, or anything else that worries you should be assessed medically, whatever is happening with the gut. Histamine intolerance in children does not yet have a test or an agreed treatment, so it is something to look at again if symptoms continue once the gut is being properly managed.
Can a blood test tell us if my child has a histamine problem?
No. The paediatric position statement says a diagnosis in children should not rest on a DAO blood test. The proposed cut-offs do not reliably separate people with symptoms from healthy people. Levels change through the day. And a level in the blood does not reflect what the enzyme is doing in the small intestine.
My child’s hives improved on a low histamine diet. Does that prove it?
Not on its own. The improvement is real, but it does not confirm that histamine caused the symptoms. In a study of adults with suspected histamine intolerance, a placebo-controlled challenge did not confirm histamine sensitivity in 50 of 59 people, and 37 reported symptoms after the placebo. That was a challenge test in adults, not a diet trial, so it cannot tell us why a child improved on a diet. If hives keep coming back, especially soon after a particular food, speak to your GP, and do not test a suspected trigger at home.
My child reacts to lots of different foods. Does that mean lots of intolerances?
Not necessarily. Symptoms after several foods do not prove several intolerances, or a histamine intolerance. A gut that is constipated, unsettled or recovering from an infection can react to ordinary amounts of ordinary food, which is one reason symptoms can seem to follow many foods. If your child has ongoing loose stools, this post explains what is usually going on. The timing and type of symptom matter, and hives soon after eating need a separate allergy assessment. Please do not cut out several foods based on the pattern alone.
References
1. Horvath A, Stróżyk A, Sybilski A, et al. The limited clinical relevance and potential risks associated with the diagnosis of histamine intolerance in children: a position statement. Alergologia Polska. 2026;13(2):80-93.
2. Nazar W, Plata-Nazar K, Sznurkowska K, Szlagatys-Sidorkiewicz A. Histamine intolerance in children: a narrative review. Nutrients. 2021;13(5):1486.
3. Bent RK, Kugler C, Faihs V, Darsow U, Biedermann T, Brockow K. Placebo-controlled histamine challenge disproves suspicion of histamine intolerance. J Allergy Clin Immunol Pract. 2023;11(12):3724-31.
4. National Institute for Health and Care Excellence. Food allergy in under 19s: assessment and diagnosis. NICE; clinical guideline CG116.
5. Di Lorenzo C, Saps M, Chumpitazi BP, et al. Lower and biliary disorders of gut-brain interaction: child and adolescent. Gastroenterology. 2026;170(6):1367-87.
6. Hoffmann KM, Gruber E, Deutschmann A, Jahnel J, Hauer AC. Histamine intolerance in children with chronic abdominal pain. Arch Dis Child. 2013;98(10):832-3.
7. Schnedl WJ, Schenk M, Michaelis S, Enko D, Mangge H. Functional abdominal pain disorders in children may be associated with food intolerance/malabsorption. Children. 2023;10(9):1444.
8. British Dietetic Association Food Allergy Specialist Group. Sensitivity to histamine and other vasoactive amines. BDA; 2025.
9. Di Nardo G, Barbara G, Cucchiara S, et al. Neuroimmune interactions at different intestinal sites are related to abdominal pain symptoms in children with IBS. Neurogastroenterol Motil. 2014;26(2):196-204.
10. Rizvi SA, Oriala C, Thomas J, Li S, Smadi Y. Identifying mast cells in gastrointestinal biopsies in pediatric irritable bowel patients. J Pediatr Gastroenterol Nutr. 2022;75(5):572-7.
11. Joneja JV. Histamine intolerance: the essential guide. Hammersmith Health Books; 2022.
12. Rosen R, Borrelli O, Faure C, et al. Rome V pediatric upper gastrointestinal disorders of gut-brain interaction. Gastroenterology. 2026;170(6):1347-66.
13. Sánchez-Pérez S, Comas-Basté O, Veciana-Nogués MT, Latorre-Moratalla ML, Vidal-Carou MC. Low-histamine diets: is the exclusion of foods justified by their histamine content? Nutrients. 2021;13(5):1395.
14. Thomas CM, Hong T, van Pijkeren JP, et al. Histamine derived from probiotic Lactobacillus reuteri suppresses TNF via modulation of PKA and ERK signaling. PLoS One. 2012;7(2):e31951.
15. National Health Service. Anaphylaxis. NHS; accessed 3 November 2026.
About the author
Bahee Van de Bor
RD, BCAPSc PGDipDiet, Specialist Paediatric Dietitian
Bahee is a specialist paediatric dietitian based at Harley Street, with over 20 years of experience including 12 years at Great Ormond Street Hospital. She is lead author of the forthcoming UK dietetic guidance for IBS and functional abdominal pain in children, and presented at ESPGHAN 2026.
Book your free 15-minute Discovery Call
