Histamine Intolerance: Symptoms, Causes, Testing, and Natural Treatment Approaches

Do you experience headaches, facial flushing, itching, nasal congestion, bloating, or diarrhea after eating certain foods?

Some people may assume that these symptoms indicate a food allergy, but another possibility is histamine intolerance.

Histamine intolerance is not a conventional allergy, nor is it a diagnosis that can be confirmed through symptoms or a single test alone. Its symptoms overlap with many conditions, including food allergy, irritable bowel syndrome, migraine, chronic urticaria, mast cell disorders, and certain gastrointestinal diseases.

Therefore, its evaluation requires a detailed medical history, linking symptoms to food intake, excluding other causes, and may include a structured dietary trial for a limited period followed by food reintroduction.

What Is Histamine?

Histamine is a chemical naturally produced by the body and has important functions in several systems.

Histamine contributes to:

• Immune and allergic responses.

• Regulation of stomach acid secretion.

• Communication between nerve cells.

• Regulation of certain vascular functions.

• The response to infection or injury.

• Certain gastrointestinal functions.

Some histamine is stored inside mast cells and basophils and can be released in response to different triggers. Histamine may also enter the body through certain foods, particularly fermented, aged, or long-stored foods.

The presence of histamine in the body is not itself a problem. A potential problem occurs when the amount of histamine consumed or released becomes greater than the body’s ability to break it down and eliminate it.

What Is Histamine Intolerance?

The term histamine intolerance is used to describe recurrent symptoms suspected to be associated with histamine consumption, resulting from an imbalance between the amount of histamine entering or being released in the body and the body’s ability to break it down.

Reduced activity of the enzyme diamine oxidase, abbreviated as DAO, is believed to contribute in some cases. This enzyme is found primarily in the intestinal lining and helps break down histamine in food before large amounts reach the bloodstream.

However, the diagnosis of histamine intolerance remains scientifically debated because its symptoms are nonspecific, and there is currently no single validated test that can conclusively confirm or exclude it.

Does Histamine Intolerance Mean Histamine Deficiency in the Body?

Many people search for “symptoms of histamine deficiency in the body,” but histamine intolerance does not usually mean that there is a deficiency of histamine.

The suspected problem is the opposite: an accumulation of histamine that exceeds the body’s ability to break it down and manage it.

Therefore, the more accurate descriptions are:

• An increased histamine burden.

• Impaired breakdown of histamine in food.

• Or increased sensitivity to an amount of histamine that other people tolerate without symptoms.

The level of histamine in the body cannot be determined from symptoms alone because headaches, flushing, itching, bloating, and palpitations can result from many other causes.

What Are the Symptoms of Histamine Intolerance?

Symptoms vary between individuals and may be affected by the amount of food, how it is stored, consuming several foods in the same meal, medications, the menstrual cycle, gastrointestinal health, and other factors.

Gastrointestinal Symptoms

These may include:

• Bloating.

• Gas.

• Abdominal pain or cramping.

• Diarrhea.

• Nausea.

• Vomiting.

• Feeling full or uncomfortable after eating.

• Heartburn in some people.

Skin Symptoms

These may include:

• Flushing of the face or skin.

• Itching.

• Urticaria.

• A sensation of heat.

• Swelling of the skin or tissues in some cases.

Nasal and Respiratory Symptoms

These may include:

• Nasal congestion.

• Runny nose.

• Sneezing.

• Wheezing.

• Shortness of breath.

Wheezing or shortness of breath requires medical evaluation. It should not be assumed to result from histamine intolerance without excluding asthma, allergy, or other causes.

Neurological and General Symptoms

These may include:

• Headache or migraine.

• Dizziness.

• Fatigue.

• Difficulty concentrating.

• Feelings of anxiety or tension.

• Sleep disturbances.

These symptoms are very common and nonspecific; therefore, they do not establish histamine intolerance on their own.

Cardiovascular Symptoms

These may include:

• Rapid heart rate.

• Palpitations.

• Low blood pressure.

• Dizziness or feeling faint.

If eating is followed by severe shortness of breath, swelling of the tongue or throat, a drop in blood pressure, or fainting, these may be signs of a severe allergic reaction requiring immediate emergency treatment, not merely a food intolerance.

When Is a Food-Related Reaction Suspected?

The possibility of a food-related reaction increases when symptoms repeatedly occur after eating specific foods, improve when those foods are avoided, and return when they are consumed again.

Symptoms may appear within minutes or several hours after eating. Guidelines emphasize the importance of a clear temporal relationship between food intake and symptom onset when evaluating suspected histamine-related reactions.

However, improvement after eliminating a large group of foods does not necessarily confirm the diagnosis. A person may improve because of reducing ultra-processed foods, alcohol, other dietary components, or because of changes in food quantity and meal patterns.

What Causes Elevated Histamine or Impaired Histamine Breakdown?

There is no single cause that applies to every case. Potential contributing factors may include:

1. Reduced DAO Enzyme Activity

DAO is primarily responsible for breaking down histamine from food within the gastrointestinal tract.

Its activity may be reduced because of genetic or acquired factors, but a low blood level alone does not establish histamine intolerance.

2. Gastrointestinal Disorders

Because DAO is present in the intestinal lining, certain intestinal diseases or inflammation may affect the ability to process histamine.

When persistent gastrointestinal symptoms are present, it may be necessary to evaluate possibilities such as:

• Celiac disease.

• Inflammatory bowel diseases.

• Lactose intolerance or fructose malabsorption.

• Irritable bowel syndrome.

• Gastrointestinal infections.

• Other disorders based on the medical history.

It should not be assumed that all bloating or diarrhea is caused by SIBO or microbiome imbalance without appropriate indications and testing.

3. Certain Medications

Some medications may affect histamine release or DAO activity. However, no prescribed medication should be stopped based on a list found online.

Medications should be reviewed with a physician to determine:

• Whether they are still needed.

• Whether a suitable alternative exists.

• Whether the timing of their use may be related to symptoms.

• The risks of stopping or changing them.

4. Alcohol

Some alcoholic beverages may contain histamine or other biogenic amines, and alcohol may also affect histamine breakdown.

5. Histamine-Rich Foods

The amount of histamine in certain foods may increase because of fermentation, aging, bacterial activity, or prolonged storage.

6. Individual and Hormonal Differences

Some women may notice changes in symptom severity during particular phases of the menstrual cycle or during the menopausal transition. However, having hormonal symptoms does not automatically indicate histamine intolerance.

Does Stress Increase Histamine?

Psychological and physical stress may affect the nervous system, immune system, and mast cells, and some people may notice that their symptoms increase during periods of stress.

However, anxiety or stress does not establish histamine intolerance. Physical symptoms associated with stress, such as palpitations, gastrointestinal disturbances, and headaches, may resemble symptoms attributed to histamine.

Therefore, the full pattern should be evaluated instead of attributing every symptom to elevated histamine.

Which Foods Are High in Histamine?

There is no standardized list that applies to everyone. The amount of histamine varies according to the type of food, its ripeness, processing method, storage conditions, refrigeration, and how long it has been kept after preparation.

Foods that may contain higher amounts include:

• Aged cheeses.

• Processed or cured meats.

• Smoked, salted, or canned fish.

• Certain fermented foods.

• Sauerkraut and kimchi.

• Soy sauce and certain fermented soy products.

• Vinegar and some products containing it.

• Certain fermented beverages.

• Cooked food left for a long time before refrigeration.

• Leftovers stored for extended periods.

There is disagreement about the classification of foods such as tomatoes, eggplant, spinach, avocado, bananas, citrus fruits, chocolate, and nuts. The concept of “histamine-releasing foods” is also not always supported by consistent evidence.

Therefore, a long list of foods should not be permanently eliminated without assessing the individual response. Histamine levels in food vary, and the lists available online are inconsistent.

What Is the Difference Between Histamine Intolerance and Food Allergy?

A true food allergy involves an immune response to a specific food protein and may occur after consuming a very small amount.

Histamine intolerance, by contrast, is believed to relate to the total histamine load and the body’s ability to break it down rather than an immune response to a specific food protein.

Both conditions may cause similar symptoms, such as:

• Urticaria.

• Itching.

• Tissue swelling.

• Vomiting or diarrhea.

• Wheezing.

• Low blood pressure.

Therefore, a low-histamine diet should not be used as a substitute for allergy evaluation, particularly when rapid or severe symptoms occur after a specific food.

What Is the Difference Between Histamine Intolerance and Mast Cell Activation Syndrome?

In histamine intolerance, the suspected problem generally focuses on histamine in food or impaired breakdown within the intestines.

Mast cell disorders, however, involve activation of these cells and the release of multiple mediators, not only histamine.

Symptoms may overlap, but the diagnostic evaluation is different. Having multiple symptoms or experiencing temporary improvement with antihistamines is not sufficient to diagnose mast cell activation syndrome.

How Is Histamine Intolerance Diagnosed?

There is currently no single, fully agreed-upon diagnostic pathway. The evaluation usually begins with a detailed medical history.

1. Identifying the Symptom Pattern

This includes:

• The type of symptoms.

• Their timing after food intake.

• Foods associated with the symptoms.

• The amount of food consumed.

• The duration of symptoms.

• Medications and supplements.

• The presence of allergies or asthma.

• The presence of gastrointestinal diseases.

• The relationship between symptoms, the menstrual cycle, and stress.

Recording food intake and symptoms for a limited period may help reveal a pattern, provided that it does not lead to random and progressively increasing food restrictions.

2. Excluding Similar Conditions

Depending on the symptoms, the physician may need to evaluate possibilities such as:

• Food allergy.

• Anaphylaxis.

• Chronic urticaria.

• Asthma or rhinitis.

• Mast cell activation syndrome or mastocytosis in selected cases.

• Celiac disease.

• Lactose intolerance.

• Fructose malabsorption.

• Irritable bowel syndrome.

• Inflammatory bowel diseases.

• Ulcers or stomach disorders.

• Certain hormonal or neurological disorders.

• Medication effects.

3. A Trial of a Low-Histamine Diet

A structured low-histamine diet may be used for a short period, usually two to four weeks, while monitoring symptoms.

If no clear improvement occurs, the diagnosis should be reconsidered instead of making the diet increasingly restrictive.

If symptoms improve, foods are gradually reintroduced to determine the individual level of tolerance. The ultimate goal is not to maintain the highest degree of restriction but to achieve the broadest diet that can be tolerated.

Is There an Accurate Test for Histamine Intolerance?

There is currently no single test that can conclusively establish histamine intolerance.

Blood DAO Enzyme Test

DAO measurement may be used as a supportive factor, but it has important limitations:

• The level may vary within the same individual.

• A blood test does not necessarily reflect enzyme activity within the intestinal lining.

• Low levels may be found in people who do not have histamine intolerance.

• There is no fully agreed-upon diagnostic cutoff value.

A population study found that a large proportion of participants had DAO levels below proposed thresholds, even though only a small number reported reactions related to histamine consumption. Other studies have also found that low DAO does not have sufficient specificity to serve as an independent diagnostic test.

Measuring Histamine in Blood or Urine

Histamine levels change rapidly and may be affected by multiple factors. Therefore, measuring histamine alone is insufficient to diagnose histamine intolerance.

Stool Histamine Testing

It is not considered a reliable standalone diagnostic test because some intestinal bacteria can produce histamine.

Histamine Skin-Prick Testing

It may measure the skin’s response to histamine, but it cannot reliably distinguish histamine intolerance from other allergic conditions.

In summary, diagnosis depends on the clinical picture, excluding similar diseases, and the response to a structured diet followed by food reintroduction rather than the result of a single test.

How Is Histamine Intolerance Treated?

Treatment depends on the severity and pattern of symptoms, associated causes, and how clearly they are linked to food.

1. A Low-Histamine Diet for a Limited Period

A low-histamine diet may help some people, but it is not intended to be a permanent lifelong diet.

It may be divided into:

Reduction Phase

Foods with higher histamine content are reduced for a defined period while symptoms are recorded.

Reintroduction Phase

Foods are gradually reintroduced in controlled amounts to determine:

• Which foods cause symptoms.

• The amount that can be tolerated.

• The effect of storage or preparation methods.

• Whether symptoms are truly associated with histamine.

Personalization Phase

An individualized diet is developed that avoids only confirmed triggers while expanding dietary choices as much as possible.

Prolonged and unnecessary dietary restrictions may lead to nutrient deficiencies, difficulty eating outside the home, fear of food, and reduced quality of life.

2. Paying Attention to Food Storage

Histamine levels may increase with storage and microbial activity.

The following steps may help:

• Choose fresh food whenever possible.

• Refrigerate cooked food promptly.

• Freeze portions that will not be eaten soon.

• Avoid leaving cooked food at room temperature for an extended period.

• Pay attention to the freshness of fish and meat and to maintaining the cold chain.

Heating food does not remove histamine once it has formed.

3. Treating Associated Diseases

If gastrointestinal disease, allergy, rhinitis, asthma, or another condition is present, treating the actual disease is more important than continuing to expand the list of prohibited foods.

4. Reviewing Medications

Medications should be reviewed with a physician and should not be discontinued without medical supervision.

5. DAO Enzyme Supplements

Supplements containing DAO are available and are usually taken before meals to help break down histamine in food within the intestines.

Some small studies suggest possible improvement in certain patients, but the evidence remains limited, and products, sources, and doses vary. Therefore, the supplement should not be considered a diagnostic test or a substitute for medical evaluation.

6. Antihistamines

A physician may decide to use histamine-receptor antagonists for a short period in certain cases, based on the type and severity of symptoms, the person’s health condition, and other medications.

Improvement with an antihistamine alone does not establish histamine intolerance because these medications may improve the symptoms of several different conditions.

7. Correcting Confirmed Nutritional Deficiencies

Certain nutrients may be associated with enzyme function and histamine metabolism, but taking random doses of supplements is not recommended.

A deficiency should be corrected when confirmed or when there is a clear clinical indication, while considering the dose and potential medication interactions.

Can Histamine Intolerance Be Cured?

The answer depends on the cause.

If symptoms are associated with a temporary factor, such as a particular medication or gastrointestinal inflammation, the ability to tolerate foods may improve after the underlying factor is addressed.

If symptoms persist, the goal is to determine the individual level of tolerance, reduce symptoms, and maintain as varied a diet as possible.

It should not be assumed that a person needs a highly restrictive diet for life.

When Should You See a Doctor?

Seek medical evaluation if symptoms:

• Are recurrent or worsening.

• Affect food intake or body weight.

• Are accompanied by persistent diarrhea or bleeding.

• Are accompanied by unexplained weight loss.

• Are accompanied by wheezing or shortness of breath.

• Are accompanied by severe palpitations or fainting.

• Lead to the elimination of multiple food groups.

• Do not improve despite following a low-histamine diet.

Swelling of the tongue or throat, difficulty breathing, a drop in blood pressure, fainting, or a rapid severe reaction after eating requires immediate emergency care.

Frequently Asked Questions About Histamine Intolerance

What Are the Symptoms of Histamine Deficiency in the Body?

Histamine intolerance does not mean histamine deficiency. The symptoms attributed to it are believed to be associated with histamine accumulation or impaired breakdown, not low histamine levels.

What Are the Symptoms of Excess Histamine?

They may include flushing, itching, urticaria, headaches, nasal congestion, bloating, diarrhea, and palpitations. However, these symptoms are nonspecific and do not establish the cause on their own.

Is Histamine Intolerance an Allergy?

It is not usually classified as a conventional immune-mediated allergy to a specific food, but its symptoms may resemble an allergy. Therefore, the two conditions should be medically differentiated.

Is the DAO Test Accurate?

It may be a supportive factor, but a low level is insufficient to confirm the diagnosis and should not be used alone.

Does Stress Increase Histamine Symptoms?

Stress may increase some symptoms in certain people through its effects on the nervous, immune, and digestive systems, but it does not establish histamine intolerance.

How Long Should a Low-Histamine Diet Be Followed?

It is usually used for a short, structured period, followed by food reintroduction. It is not recommended to turn it into a permanent, highly restrictive diet without a clear need.

Are Probiotics Suitable for Histamine Intolerance?

There is no single answer for everyone. The characteristics of bacterial strains vary, and individual responses may differ. Therefore, probiotics should not be selected based on a general description or the assumption that all types reduce histamine.

Conclusion

Histamine intolerance may be considered when gastrointestinal, skin, respiratory, or neurological symptoms repeatedly occur after certain foods.

However, the symptoms are nonspecific, and no single test confirms the diagnosis. A proper evaluation includes linking symptoms to food, excluding allergies and similar diseases, assessing the gastrointestinal system when indicated, following a low-histamine diet temporarily and systematically, and then reintroducing foods.

The goal is not to eliminate as many foods as possible, but to reach the most likely diagnosis and develop a varied diet appropriate for the individual level of tolerance.

For a comprehensive assessment of your symptoms and associated health factors, and to develop a dietary and health plan suitable for your condition, you can book a consultation with Dr. Samar Shadly.

Dr. Samar Shadly, MD, IFMCP
Consultant in Internal Medicine and Pulmonary Diseases
Certified Functional Medicine Physician
Consultations are currently available online.

Selected References

• Jochum C. Histamine Intolerance: Symptoms, Diagnosis, and Beyond. Nutrients. 2024.

• Bent R, et al. Placebo-Controlled Histamine Challenge Disproves Suspicion of Histamine Intolerance. J Allergy Clin Immunol Pract. 2023.

• Reese I, et al. Guideline on Management of Suspected Adverse Reactions to Ingested Histamine.

• Evidence for Dietary Management of Histamine Intolerance. International Journal of Molecular Sciences. 2025.

• Evaluation of Serum Diamine Oxidase as a Diagnostic Test for Histamine Intolerance. Nutrients. 2023.