Everyone knows what allergies are, but Histamine Intolerance, affecting just 1% of the population, is less well-understood. The two conditions have different causes and treatments, but virtually the same symptoms. If you have allergies or food intolerances, it’s worth considering if you actually may be suffering from Histamine Intolerance.

What is Histamine Intolerance?

Histamine Intolerance resembles allergies, but it has a different cause. It’s an overload of histamine caused by a problem with the DAO or HNMT enzymes.

Histamine Intolerance (HIT) is not a sensitivity to histamine—it’s what happens when too much histamine builds up in your body. A little is OK, a lot is not.

Histamine is essential to life. It helps regulate many systems in your body, including your appetite, sleep cycle, motivation, learning, digestion and immune function. And yes, it makes you itch, as part of your inflammatory process.

The symptoms of histamine intolerance are:

Sneezing
Runny, itchy nose
Watery, itchy eyes
Coughing
Rash, eczema
Skin itching and swelling
Headaches
Brain fog
Bloating
Nausea
Low libido
Symptoms of ADHD

In severe instances, symptoms can also include:

Digestive upset
Irregular heart rate
High blood pressure
Anxiety

Several conditions may contribute to histamine intolerance:

Some IBS cases – IBS (Irritable Bowel Syndrome) patients often have more mast cells in their gut than normal, which could cause higher levels of histamine in their digestive systems.
Some SIBO cases – SIBO (Small Intestinal Bacterial Overgrowth) can trigger mast cell release and a resulting histamine overload.
Some menstrual pain cases – many women with histamine sensitivity experience severe cramping during their periods. This may be because histamine increases the production of estrogen, which stimulates the release of prostaglandin, which in turn causes uterine contractions.

With allergies, any exposure to the offending food or substance will trigger a response. In contrast, with HIT, you have the ability to tolerate histamine up to a limit. When you reach that limit, you can suddenly find yourself suffering from what feels like an allergy attack. It’s similar to filling up a glass of water—no problem, unless you keep pouring water in after the glass is full. And then you have histamine running all over the place.

How I Identified My HIT

Learning about HIT ended a years-long mystery for me. At seemingly random times, my face would swell up around my eyes, and my skin would and become red, dry and itchy. It made me look like I’d been punched in the face, and I’ve stayed home from work because of it.

I’d always assumed I was having an allergic reaction to a product I put on my face, or possibly to something I ate. But my reaction was inconsistent; one day a product or food would be fine, and another it wouldn’t. I had never been able to pinpoint what the triggers were.

One day a year ago I was out to dinner with my husband at a new Italian restaurant. I had a vinaigrette salad, tomato and spinach pasta topped with loads of parmesan, and red wine. I may as well have set my face on fire.

In the morning I woke up with the swollen, red, itchy face and eyes, and this time, the most severe case of heartburn I had ever experienced. These symptoms lasted for two days, and I was miserable. The foods I ate are among my favorites—I eat them all the time, although not always together. That night I had eaten a particularly large concentration of those foods, which are high in histamine, at the same time.

That’s when I dived deep into the research to find out what was going on with me, and I learned about HIT. I felt it described what was happening to me perfectly. I also found out from a third-party analysis of my 23andMe data that I was susceptible to HIT.

I decided not to have a doctor formally diagnose me. I went ahead and adopted the eating and lifestyle guidelines below, and I have not had a flare-up since. If you suspect you may have HIT, and would like a physician to confirm it, you can get a skin prick or blood test.

What Causes Histamine Overload?

Your body breaks down histamine with two enzymes: DAO (diamine oxidase) and HNMT (histamine N-methyltransferase). If either of these enzymes malfunction, histamine overload is the result. Some people have a genetic condition that prevents proper production of these enzymes.

For unknown reasons, HIT doesn’t show up until middle age in most people.

What To Do if You Have HIT

You need a four-point strategy:

Avoid foods that contain or liberate histamine
Reduce excess histamine in the body
Increase activity of DAO and HNMT
Modify your lifestyle

1. Avoid foods that contain or liberate histamine

Histamine accumulates in foods with age and bacterial activity. Hence, aged and fermented foods contain high levels of histamine (but they are not the only foods that do). Avoid these foods, supplements and additives:

Sauerkraut and kimchi
Cider, kombucha, beer and wine (red wine has more than white)
Pickles
Tofu, natto, seitan and other fermented soy products
Yogurt, buttermilk and kefir
Aged cheese
Dried fruit
Cured and fermented fish/fish products
Cured meats like sausage, pepperoni and salami
Canned and processed foods (e.g., tomato paste)
Vinegar
Yogurt
Yeast and yeast products
A few fresh foods: spinach, tomatoes, eggplant, avocados, mushrooms, bananas, cherries
Soy, green peas, red beans, sugar and sweet peas
Some meats: pork is the worst offender. Grilling can make it worse
Alcoholic beverages, especially wine
Green tea
Chile powder, cinnamon and cloves

Some foods trigger the release of histamine. Avoid these “histamine liberators:”

Citrus fruits
Papayas, strawberries, pineapple, plum, kiwi
Walnuts and cashews
Cocoa and chocolate
Tomatoes
Sulfites in red wine
Egg whites
Licorice
Wheat germ
Some probiotics from the Lactobacillus family
Artificial colors and additives, including azo dyes, sunset yellow, carmoisine, tartrazine, ponceau 4R, quinoline yellow, Allura red AC, and sodium benzoate

People with HIT may have different degrees of tolerance. Some people may react to a small serving of a high-histamine food; whereas others may need to eat a number of high-histamine foods at once to spark a reaction.

2. Reduce excess histamine in the body

Try these supplements:

Quercetin—a plant flavonoid and antioxidant. One of the best natural antihistamines; helps prevent histamine reactions
Forskolin—a compound extracted from a plant in the mint family. It stabilizes mast cells and relaxes muscles in the lungs.
Astragalus—a compound from a plant also known as milk vetch. A powerful antioxidant that can stabilize mast cells in the intestines and nasal passages.
Theanine—an amino acid found in green and black tea that crosses the blood-brain barrier. In animal studies it stabilized mast cells and prevented histamine release.
Curcumin—the active compound in turmeric with strong anti-inflammatory properties. It helps prevent mast cells from releasing histamine.
Holy Basil (Tulsi)—in animal studies, it prevented histamine release.
DAO—you can directly supplement the enzyme that breaks down histamine

3. Increase DAO/HMNT activity

Avoid these foods and supplements that can interfere with DAO and HNMT activity:

Alcohol
Energy drinks
Green tea
Black tea
Mate tea
Raw egg whites
Some yogurt, depending on bacteria type
Carnosine – it can compete with histamine to bind with DAO

These supplements may help DAO work better, or otherwise improve HIT, according to Medical News Today, an evidence-based, medically-reviewed website:

Vitamin B-6, which helps DAO break down histamine
Vitamin C to help lower histamine blood levels and help DAO break down histamine
Copper, which helps raise DAO blood levels slightly and helps DAO break down histamine
Magnesium that can raise the allergic response threshold
Manganese that can enhance DAO activity
Zinc to help DAO break down histamine (it may also have anti-inflammatory and anti-allergic properties)
Calcium to help reduce hives and skin flushing
Vitamin B-1
Vitamin B-12
Folic acid

4. Modify your lifestyle

Some lifestyle choices can help control your HIT:

Mitigate stress—during stress, your body releases cortisol and activates mast cells, which may cause excess histamine to be released. In addition, Nerve Growth Factor (NGF), which also triggers histamine, is released. These processes may play a role in auto-immune conditions like multiple sclerosis and rheumatoid arthritis. Theoretically, less stress can mean less histamine and fewer symptoms of inflammation.

Treat infections – people with chronic infections have highger histamine levels, likely through excess activation of mast cells. Examples include:
- H.pylori – causes inflammation that can lead to ulcers and sometimes cancer of the stomach and small intestine. H. pylori also increases HDC, the enzyme that manufactures histamine.

Ask your doctor if you can adjust your medications—some medications cause increased histamine. This list combines information Medical News Today and from selfhacked.com, both evidence-based, medically-reviewed health websites:
- ACE Inhibitors—these blood pressure medications increase bradykinin, a protein that causes blood vessels to dilate. Bradykinin causes histamine to release, possibly through increasing calcium in cells.
  - Benazepril (Lotensin)
  - Captopril
  - Enalapril (Vasotec)
  - Fosinopril
  - Lisinopril (Prinivil, Zestril)
  - Moexipril
  - Perindopril
  - Quinapril (Accupril)
  - Ramipril (Altace)
  - Trandolapril
- Alprenolol, a beta-blocker often prescribed for high blood pressure
- Aminophylline, an asthma medication
- Antipsychotics
- Aspirin
- Cefotiam, an antibiotic
- Cefuroxime, an antibiotic
- Chloroquine, an antibiotic
- Cimetidine, an antacid and H2R blocker; despite being an antihistamine, this drug significantly inhibits DAO
- Dihydralazine, prescribed for high blood pressure
- Diuretics
- Gastrointestinal medications
- GERD medications
- Heart medications
- Heparin, an anticoagulant
- Imidazoles, including many fungicides
- Isoniazid, a tuberculosis drug
- Malaria drugs
- Monoamine oxidase inhibitors (MAOIs, a class of antidepressants)
- Muscle relaxants
- Naproxen
- Opioid analgesics, including morphine and codeine
- Pain medications
- Theophylline, an airway medication
- Tuberculosis drugs
- Verapamil, a calcium channel blocker often prescribed for high blood pressure
- Contrast media, given before medical imaging procedures

Identify and Control Food Allergies—people with food allergies make more histamine and have more mast cells in their guts, contributing to their allergic symptoms

Avoid Environmental Toxins—exposure to the following are associated with increased histamine release:
- Mold, including Aspergillus and Stachybotrys
- Algae
- Bacteria
- Volatile Organic Compounds (VOCs)

Smoking—nicotine causes histamine to be released

What Else Can You Do?

One of the most helpful actions you can take is to keep a food diary. This will help you identify what it takes to trigger your reaction. You can download a helpful, free diary here at the HistamineIntolerance.org/uk website.

An app called Food Intolerances may also be helpful. It has good reviews and can help you track what to eat and not eat. It’s available at the apple App store and Google Play.

HIT can range from slightly annoying to unbearable. But there is much that you and your doctor can do to make it manageable.

I hope these tips help. The best of health to you!

Did you know there are significant health downsides to taking collagen supplements (histamine overload is just one)? Read more here.

Curious what the healthiest apple variety is? There is one! Find out here.

Interested in taking MSM to support collagen or help with your arthritis? Read why it may be a good idea for you here.

Resources

Laura Maintz, Natalija Novak, Histamine and histamine intolerance, The American Journal of Clinical Nutrition, Volume 85, Issue 5, May 2007, Pages 1185–1196, https://doi.org/10.1093/ajcn/85.5.1185.
Chung, B. Y., Park, S. Y., Byun, Y. S., Son, J. H., Choi, Y. W., Cho, Y. S., Kim, H. O., & Park, C. W. (2017). Effect of Different Cooking Methods on Histamine Levels in Selected Foods. Annals of dermatology, 29(6), 706–714. https://doi.org/10.5021/ad.2017.29.6.706.
Thomas CM, Hong T, van Pijkeren JP, Hemarajata P, Trinh DV, et al. (2012) Histamine Derived from Probiotic Lactobacillus reuteri Suppresses TNF via Modulation of PKA and ERK Signaling. PLOS ONE 7(2): e31951. https://doi.org/10.1371/journal.pone.0031951.
Wadu Mesthri Deepika Priyadarshani, Sudip K. Rakshit. (2011) Screening selected strains of probiotic lactic acid bacteria for their ability to produce biogenic amines (histamine and tyramine). IFST (Institute of Food Science Technology) 46(10), 2062-2069. https://doi.org/10.1111/j.1365-2621.2011.02717.x.
Mu, Q., Tavella, V. J., & Luo, X. M. (2018). Role of Lactobacillus reuteri in Human Health and Diseases. Frontiers in microbiology, 9, 757. https://doi.org/10.3389/fmicb.2018.00757.
Schnedl, W. J., Lackner, S., Enko, D., Schenk, M., Holasek, S. J., & Mangge, H. (2019). Evaluation of symptoms and symptom combinations in histamine intolerance. Intestinal research, 17(3), 427–433. https://doi.org/10.5217/ir.2018.00152
Hanusková, E., & Plevková, J. (2013). Histamínová intolerancia [Histamine intolerance]. Ceskoslovenska fysiologie, 62(1), 26–33.
Kovacova-Hanuskova, E., Buday, T., Gavliakova, S., & Plevkova, J. (2015). Histamine, histamine intoxication and intolerance. Allergologia et immunopathologia, 43(5), 498–506. Götz M. (1996). Pseudoallergien sind Histaminintoleranzen [Pseudo-allergies are due to histamine intolerance]. Wiener medizinische Wochenschrift (1946), 146(15), 426–430.

Is it Allergies, or Histamine Intolerance?