Four-year-old Xiaohao has developed a new habit of stomachaches since starting kindergarten.
There are 1-2 days every week when he needs to be picked up after lunch due to stomach pain, sometimes accompanied by diarrhea and rashes, but he recovers shortly after returning home.
His mother took Xiaohao to the hospital for a series of tests, but no abnormalities were found. After several visits, the doctor asked for the kindergarten’s menu, and found that every day Xiaohao had a stomachache, there was tomato and scrambled eggs for lunch.
The mother was puzzled, as Xiaohao had never been allergic to these two foods before, so it should not be caused by allergies.
However, to rule out the possibility of food-induced abdominal pain, the doctor asked the mother to instruct the teacher to let Xiaohao eat this dish as little as possible. Sure enough, Xiaohao did not have any stomach pain in the following week, and the pain reoccurred when he ate the dish again.
What could be the reason? Let’s talk about this “food assassin” on the dining table.
What causes Xiaohao’s stomachache?
Xiaohao’s condition is likely not food allergy but histamine intolerance.
Upon hearing the term ‘histamine intolerance’, many people may be unfamiliar with it. In fact, there are two ‘little cleaners’ in the human body—— DAO enzyme and HNMT enzyme, which are specifically responsible for breaking down histamine in food.
However, if there are too few ‘cleaners’ or their capacity is insufficient, or if various factors (infections, foods, medications, dysbiosis, etc.) interfere with their normal functioning, the ingested histamine cannot be cleared in time, accumulates in the body, and causes trouble, leading to histamine intolerance [1-3]. The exact causes and mechanisms are not yet fully understood.
As shown in the figure below, unlike histamine poisoning caused by consuming foods with a large amount of histamine (e.g., spoiled fish), histamine intolerance is more about these two enzymes not fully playing their role in breaking down histamine.
About 1% of the world’s population may be troubled by histamine intolerance, of which 80% are adults, and boys have a slightly higher proportion among children[4].
Excessive histamine entering the body can cause many discomforts,mainly gastrointestinal discomfort such as abdominal pain, diarrhea, bloating, nausea, and vomiting, skin(hives, erythema), brain(headache, dizziness), respiratory tract(runny nose, cough), cardiovascular system(accelerated heartbeat)may also have corresponding manifestations.
However, these symptoms are often similar to those of food allergies and irritable bowel syndrome, which also brings difficulties to the diagnosis of histamine intolerance.
How can you know if it’s histamine intolerance?
Determining whether it is histamine intolerance requires the following steps[1,2,4]:
1. Multiple symptoms
At least 3 symptoms related to histamine intolerance (involving multiple systems) or 2 gastrointestinal symptoms (such as chronic abdominal pain, diarrhea, vomiting), symptoms occur within 4 hours after consuming high-histamine foods.
2. Dietary exclusion and provocation test
Exclusion period: Follow a strict low-histamine diet for 4-8 weeks and record changes in symptoms (diet diary required); Reintroduction period: Gradually add high-histamine foods and observe the recurrence of symptoms.
Special reminder ⚠️: Keep a food diary, and avoid foods under the guidance of a doctor.
3. Laboratory tests
Since not many institutions currently offer the following tests, this step can be skipped:
Serum DAO activity
Core indicator: DAO activity ≤ 10 U/mL (pediatric reference values need to be adjusted according to age).
Urinary histamine metabolites
Test the concentration of histamine (HA) and 1-methylhistamine (1-MH) in urine, elevated levels suggest metabolic abnormalities.
Genetic testing
DAO gene polymorphisms (e.g., rs1049793, rs2052129) or HNMT gene mutations are related to reduced enzyme activity.
4. Exclude other diseases
Food allergies
Allergy tests (e.g., specific IgE, skin prick tests) are positive, and symptoms may appear more quickly.
Gastrointestinal diseases
For example, irritable bowel syndrome(often related to mental stress, discomfort is limited to the gastrointestinal tract, low-histamine diet has limited effect), celiac disease(anti-tissue transglutaminase antibody positive, low-histamine diet is ineffective), lactose intolerance(hydrogen breath test positive, and symptoms are limited to the digestive tract). Mast cell-related diseases
Systemic mastocytosis (serum tryptase persistently elevated, bone marrow biopsy shows mast cell infiltration), chronic urticaria (long-term antihistamine medication required, low-histamine diet is ineffective). Note: Infants may experience symptoms triggered by biogenic amines in breast milk, but diagnosis should be approached with caution!
A low-histamine diet is the core, it is necessary to avoid some “high-risk foods” and try to eat fresh, less processed foods, but avoid long-term dietary restrictions. The specific diet plan should be guided by a nutritionist to prevent malnutrition in children.
For cases like Xiaohao, in addition to paying attention to tomato and scrambled eggs, there are other foods to be aware of, mainly including[1-2,4-5]:
1. High-histamine “high-risk households”
Fruits and vegetables: Eggplant, tomatoes and tomato sauce, spinach Fermented foods: Alcohol, aged cheese(e.g., blue cheese), sauerkraut, soy sauce, etc. Processed meats and fish: Such as sausages, ham, certain frozen, smoked, and canned fish. Some spoiled protein-rich foods, especially fish(mackerel, tuna, sardines, herring, sardines, etc., dark-skinned red-fleshed saltwater fish).
2. “Troublemakers” that promote the release of histamine
Citrus fruits(oranges, grapefruit), strawberries, kiwi, egg whites, chocolate, nuts. Medications: Nonsteroidal anti-inflammatory drugs(such as ibuprofen), contrast agents, muscle relaxants, anesthetics, antiarrhythmic drugs, diuretics, isoniazid, doxycycline, etc.
3. “Pig teammates” that slow down the “cleaners”
Bananas, pineapples: Halve the work efficiency of DAO enzymes. Snacks with preservatives: Such as dried plums, spicy strips, which can interfere with enzyme activity.
Additionally, there are adjuvant therapies:
1. DAO enzyme supplements
Take before meals to help break down histamine in food (doctor assessment required, mainly used in adults, lack of clinical application data in children)[1].
2. Medications
Severe cases use antihistamines(under doctor’s guidance), but not for long-term dependence[4].
3. Remove secondary factors
Treat accompanying diseases such as allergies, gastrointestinal infections, irritable bowel syndrome, etc., and avoid medications that promote histamine release.
Most children improve with dietary control, but because each child’s situation is different, parents need to work closely with doctors and dietitians to gradually find a suitable diet plan for their child, while also paying attention to other health issues that may accompany. Although there is uncertainty in diagnosis and treatment,active management can significantly improve children’s quality of life[1,4,7].
In summary, histamine intolerance is like a child’s body being “picky eaters”, and we need to use wisdom to be the “interpreters”.
Note: Children’s DAO activity fluctuates greatly, and repeated testing is needed to improve accuracy.
How to treat histamine intolerance?
Can histamine intolerance be completely cured?
Keep a daily food diary and work in coordination with doctors and dietitians.
Remember – avoiding “assassin foods” is not about depriving delicious food, but about making children eat safer!
References
