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Histamine Intolerance or Allergies: How to Tell Which One You Have
Immune Health · Allergies
Itching, flushing, congestion, hives, or an upset stomach after a meal can all feel like an allergic reaction. But not every histamine-driven symptom comes from an allergy.
When determining whether you have histamine intolerance or an allergy, it comes down to either an overactive immune system or a clearance response. In an allergy, the immune system overreacts. In histamine intolerance, the body struggles to clear histamine fast enough. Knowing which one you're dealing with shapes how you test for it and how you manage it.
Allergies: An Immune System Overreaction
In 2021, nearly one-third (31.8%) of U.S. adults aged 18 and older had a diagnosed seasonal allergy, eczema, or food allergy. (1)
Seasonal, animal dander, and food allergies have one thing in common: they are overreactions to harmless substances. The immune system mistakenly identifies a substance (pollen, shellfish, dog dander, or thousands of otherwise harmless substances) and mounts an attack on it. This immune cascade produces antibodies called IgE to fight the imaginary invader. As a result, mast cells release inflammatory chemicals to protect the body from the imagined attack. (2)
The Histamine Response
One chemical released from mast cells during an allergic reaction is a signaling molecule called histamine. The histamine response results from histamine binding to certain cell receptors, which in turn triggers an allergic reaction.
Symptoms of the Histamine Response
- Itching
- Tissue swelling
- Mucus production
- Blood vessel dilation
Allergies take many forms, and knowing the range helps explain why symptoms can look so different from one person to the next.
Types of Allergies
- Additives in food, such as dyes, and food proteins
- Animal dander
- Insect stings and bites
- Dermatitis, including eczema or contact dermatitis such as a latex allergy, poison oak, or poison ivy
- Cell-mediated allergies such as eosinophilic esophagitis, a chronic immune/antigen-mediated disease involving eosinophilic inflammation (symptoms include difficulty swallowing, heartburn, or chest pain)
- Hives from common household or skin care products, plants, etc.
- Sinusitis
- Allergic asthma
- Allergic rhinitis and rhinosinusitis (runny nose, sinus pain)
- Allergic conjunctivitis (watery, red, swollen eyes)
- Mold or mites (2)
Allergies Can Develop at Any Age
Even if you sailed through childhood and early adulthood without having allergies, you are not in the clear. Many people develop allergies later in life.
Common Triggers for Adult-Onset Allergies
- Moving to another location and climate that has different pollens, trees, and grasses
- Moving into an older home that may have dust mites or mold
- Changes in hormones, such as during pregnancy or menopause
- Changes in immune function as we age, which can lead to exaggerated responses
- Stress, which can exacerbate immune reactions, whether from a medical diagnosis or a situational factor (3)
Testing for Allergies
Allergy testing can be quite simple or complicated. Depending on the symptoms and severity, testing may include:
Elimination and Reintroduction
Removing the suspected substance, such as a particular food (dairy, eggs, nuts, fish, and wheat are common allergens) or skin care product, then reintroducing it after enough time has passed while watching for reactions.
Skin Prick Testing
Introducing small amounts of different allergens under the skin's surface and observing for a reaction, such as a raised bump.
Blood Tests
Measuring specific allergen IgE antibodies. (4)
Allergy Management
Several ways to manage allergies exist once the allergen has been identified.
Immunotherapy involves gradually exposing the immune system to increasing doses of the allergen as the body tolerates the substance. One popular form of this idea uses locally sourced honey, based on the belief that a small amount of pollen could benefit plant-based allergies. However, this practice can backfire and worsen allergies. Use locally sourced honey with caution and consult your care provider before using it.
Several botanicals have also been studied for their effects on mast cells and allergic inflammation:
Quercetin and Luteolin
Dietary flavonoids that act as natural mast cell stabilizers, which prevent mast cells from degranulating and releasing histamine. (5)
Pine Bark
A strong anti-inflammatory and antioxidant that can support mast cell stability. (6)
Butterbur
Especially effective at inhibiting inflammatory chemicals responsible for airway constriction and nasal congestion. (7)
Apigenin
Commonly found in parsley and celery, apigenin helps balance the immune system and reduce the body's overreaction to harmless allergens. (8)
Because these compounds work on overlapping pathways, some formulas combine them. TWC's HistaCalm, for instance, brings quercetin, luteolin, pine bark extract, butterbur, and apigenin together in one daily capsule for people looking to support mast cell stability. Over-the-counter or prescription antihistamines and/or nasal and topical corticosteroids can also relieve symptoms.
But what if your symptoms look like an allergy and testing doesn't find one? That's where histamine intolerance comes in.
What Is Histamine Intolerance?
When people experience a histamine response without a true allergy, it is often histamine intolerance. This happens when the body, often due to reduced or impaired production of the digestive enzyme DAO, fails to break down histamine from foods fast enough. The result is a dose-dependent buildup that mimics allergic symptoms.
Histamine Intolerance Symptoms
- Headache or migraine
- Flushing of the neck or face
- Hives
- Nasal congestion
- Heart palpitations, tachycardia, low blood pressure
- Digestive distress: nausea, vomiting, abdominal pain, diarrhea, or constipation
- Menstrual cramps (9,10,17)
Causes of Histamine Intolerance
Genetic Variations
Genetic variations that reduce DAO activity have been associated with histamine intolerance. (11)
Gut Dysbiosis and Inflammation
One study found that healthy gut bacteria were significantly lower and histamine-secreting bacteria significantly higher in patients with histamine intolerance than in healthy subjects. The theory is that intestinal dysbiosis, which impairs the DAO enzyme's ability to degrade histamine properly, could cause histamine buildup. (12,13)
Medications
Drugs that inhibit DAO activity include cimetidine (trade name Tagamet), which reduces stomach acid production, and verapamil, a prescription medication used to treat high blood pressure. (14)
MTHFR (methylenetetrahydrofolate reductase) mutations may also play a role. MTHFR is a gene that helps process and regulate homocysteine levels in the body by helping your body produce the folate required to break down homocysteine. (15) MTHFR has other variants associated with health issues that can increase risks for blood clots, depression, and anxiety. Up to 40% of people carry at least one variant of this gene. (15)
Testing for Histamine Intolerance
Several tests can help your healthcare provider diagnose histamine intolerance:
Common Approaches
- Symptom assessment, including evaluation for headaches, digestive issues, respiratory issues, and skin reactions
- An elimination diet: following a low-histamine diet for a set period of time, usually a month, then gradually reintroducing histamine-containing foods and observing any reactions
- Blood tests, which could include measuring DAO levels or MTHFR mutations
- A gut microbiome test, which could reveal high histamine-producing bacteria. This test is not diagnostic and requires a functional medicine practitioner to interpret the results. (16)
Histamine Intolerance Management
DAO Supplementation
Supplementing with the DAO enzyme to help break down dietary histamine.
Vitamin C
Vitamin C has been shown to reduce histamine levels. (17)
Low-Histamine Diet
Avoiding high-histamine foods, which include fermented foods, aged cheeses, alcohol, and packaged and processed meats. (18)
Allergy or Intolerance: Why the Difference Matters
An allergy is the immune system overreacting to something harmless. Histamine intolerance is the body falling behind on clearing histamine it already has. The symptoms can look nearly identical, but the testing and management paths are different.
Understanding that difference can help you identify potential triggers and choose appropriate testing and management strategies. Because symptoms overlap and the underlying causes may be complex, working with a qualified healthcare provider is the most reliable way to find the right approach for your individual situation.
Featured Product
HistaCalm · Histamine Balance
Daily Support for Mast Cell Stability
HistaCalm is a doctor-formulated flavonoid and botanical complex combining quercetin, luteolin, pine bark extract, butterbur, and apigenin, the same compounds discussed above. It's designed to support healthy histamine breakdown and mast cell stability without the drowsiness.
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References
- Ng, A. E., & Boersma, P. (2023). Diagnosed allergic conditions in adults: United States, 2021 (NCHS Data Brief No. 460). National Center for Health Statistics. https://www.cdc.gov/nchs/products/databriefs/db460.htm
- https://www.msdmanuals.com/professional/immunology-allergic-disorders/allergic-autoimmune-and-other-hypersensitivity-disorders/overview-of-allergic-and-atopic-disorders
- https://scienceinsights.org/why-do-allergies-develop-later-in-life/
- https://www.sciencedirect.com/science/article/abs/pii/S1081120623011365
- Leonard, J. (2024, February 27). Top 8 natural antihistamines for allergies. Medical News Today.
- Sharma SC, Sharma S, Gulati OP. Pycnogenol inhibits the release of histamine from mast cells. Phytother Res. 2003 Jan;17(1):66-9. doi: 10.1002/ptr.1240. PMID: 12557250.
- EBSCO CAM Review Board. (2024). Natural treatments for allergies. EBSCO Research Starters.
- Li H, Zhang H, Zhao H. Apigenin attenuates inflammatory response in allergic rhinitis mice by inhibiting the TLR4/MyD88/NF-κB signaling pathway. Environ Toxicol. 2023 Feb;38(2):253-265. doi: 10.1002/tox.23699. Epub 2022 Nov 9. PMID: 36350155.
- Comas-Basté, O., Sánchez-Pérez, S., Veciana-Nogües, M. T., Latorre-Moratalla, M. L., & Vidal-Carou, M. C. (2020). Histamine intolerance: The current state of the art. Biomolecules, 10(12), 1816. https://doi.org/10.3390/biom10121816
- Jochum C. Histamine Intolerance: Symptoms, Diagnosis, and Beyond. Nutrients. 2024 Apr 19;16(8):1219. doi: 10.3390/nu16081219. PMID: 38674909; PMCID: PMC11054089.
- Duelo A, Comas-Basté O, Sánchez-Pérez S, Veciana-Nogües MT, Ruiz-Casares E, Vidal-Carou MC, Latorre-Moratalla ML. Pilot Study on the Prevalence of Diamine Oxidase Gene
- in Patients with Symptoms of Histamine Intolerance. Nutrients. 2024 Apr 12;16(8):1142. doi: 10.3390/nu16081142. PMID: 38674832; PMCID: PMC11054051.
- Sánchez-Pérez S, Comas-Basté O, Duelo A, Veciana-Nogües MT, Berlanga M, Latorre-Moratalla ML, Vidal-Carou MC. Intestinal Dysbiosis in Patients with Histamine Intolerance. Nutrients. 2022 Apr 23;14(9):1774. doi: 10.3390/nu14091774. PMID: 35565742; PMCID: PMC9102523.
- Leitner R, Zoernpfenning E, Missbichler A. Evaluation of the inhibitory effect of various drugs / active ingredients on the activity of human diamine oxidase in vitro. Clin Transl Allergy. 2014 Jul 18;4(Suppl 3):P23. doi: 10.1186/2045-7022-4-S3-P23. PMCID: PMC4127955.
- WebMD. (n.d.). MTHFR gene mutation: Tests, symptoms, and treatment. https://www.webmd.com/a-to-z-guides/mthfr-gene-mutation-tests-symptoms-treatment
- Clemetson CA. Histamine and ascorbic acid in human blood. J Nutr. 1980 Apr;110(4):662-8. doi: 10.1093/jn/110.4.662. PMID: 7365537.
- Superpower. (2026, August 31). Histamine-producing species: Mapping the microbes that make histamine. https://superpower.com/guides/gut-health/histamine-producing-species-test
- WebMD. (n.d.). Foods high in histamine. https://www.webmd.com/diet/foods-high-in-histamine
Author
This article is not intended to diagnose or treat any symptoms. Consult with your care provider for all your healthcare needs.
