What Is Histamine?
Histamine is a natural substance produced by our immune cells as a response to stressful situations, usually after exposure to an allergen. When it is released, different parts of the body may experience effects such as:
- Skin: itching, swelling, rashes, hives
- Eyes: itching, burning
- Nose: itching, sneezing, runny nose
- Lungs: wheezing, coughing
- Digestive system: cramps, diarrhea
- Blood vessels: headaches
You may also have experienced a histamine response after a mosquito bite or bee sting. The swelling, redness, and itching are the direct result of histamine being released at the site of the injury. Histamine is also involved in allergic reactions, including the seasonal allergies many people experience.
Histamine's role is to trigger an immediate inflammatory response. It acts as a "red flag" for the immune system, alerting the body to potential threats.
It causes blood vessels to widen so that white blood cells can reach an infection or other threat more quickly.
It is important to understand that histamine is both produced by the body and a substance that can come from the foods we eat. Some foods also stimulate the body to produce more histamine.
What Is Histamine Intolerance?
Histamine intolerance generally refers to a person's inability to tolerate foods that are high in histamine or foods that trigger histamine release as part of their diet. Unlike an allergy, however, histamine intolerance can vary in severity. For many people with histamine intolerance or sensitivity, symptoms appear when their histamine level rises above a certain threshold. One way to understand this idea is to imagine your body as a glass of water. Foods that contain histamine or trigger its release add water to the glass, but symptoms may appear only when the glass overflows. Even otherwise healthy people without day-to-day histamine issues can develop histamine-related symptoms in cases such as scombroid food poisoning after eating spoiled fish.
People with histamine intolerance may experience fewer symptoms when they avoid foods that trigger them. This can be difficult to work out because symptoms vary from person to person, and it is not always easy to tell whether histamine intolerance is involved. Each person may need to identify their own tolerance threshold and which foods they can or cannot tolerate, much like the process used during the AIP protocol reintroduction phase/elimination phase.
What Causes Histamine Intolerance?
If you experience symptoms that may be related to histamine intolerance, it is important to explore possible causes with a qualified healthcare professional. Addressing an underlying issue may sometimes help make the symptoms more manageable. Some possible factors to consider include:
- SIBO (small intestinal bacterial overgrowth) - SIBO may contribute to histamine intolerance when an overgrowth of bacteria produces excess histamine from undigested food.
- Leaky gut syndrome - I have already covered this topic in detail, so you can read the dedicated article
- Methylation - Some people with impaired methylation, whether genetic or related to another factor, may experience changes in histamine tolerance.
- Genetics - Alongside the genetic component of methylation, some people may have variants affecting enzymes that break down histamine, such as diamine oxidase or DAO. Lower enzyme activity may reduce a person's ability to tolerate histamine.
- Medications - Some medications can inhibit DAO enzyme activity and may contribute to symptoms associated with histamine intolerance.
Which Foods Are High in Histamine or Inhibit Histamine Breakdown?
Many foods contain histamine, trigger the body to release histamine, or interfere with its breakdown. For people with histamine intolerance, adjusting their diet to remove or limit these foods may help reduce symptoms. Careful reintroduction can then help them understand their personal tolerance threshold.
Foods High in Histamine
- Alcoholic drinks, especially beer and wine
- Cheese, especially aged varieties
- Dried fruit
- Fermented foods, including sauerkraut, kombucha, kefir, and yogurt
- Aged or processed meat products, including bacon, salami, and deli meats
- Smoked foods, especially seafood
- Seafood, unless it is caught, cooked, and eaten very quickly
- Foods containing vinegar, including pickles and olives
- To a lesser extent, fruits and vegetables such as citrus fruit, avocado, eggplant, mushrooms, spinach, and tomatoes
Foods That May Trigger Histamine Release
- Alcoholic drinks
- Bananas
- Chocolate
- Eggs
- Fish
- Milk
- Papaya
- Pineapple
- Shellfish
- Strawberries
Here Is a List of Lower-Histamine Foods:
- Cooked meat and poultry, fresh or frozen
- Fresh fish
- Cooked eggs
- Rice
- Fresh fruit: mango, pear, watermelon, apple, melon
- Fresh vegetables, except those listed above
- Milk alternatives: coconut milk, rice milk, hemp milk, almond milk
- Cooking oils: olive oil, coconut oil
- Herbal teas
Testing for Histamine Intolerance
Elimination and Reintroduction
One practical approach is to remove the foods listed above for 30 days and then reintroduce them one at a time, following appropriate guidance. I am not a doctor, and this is not medical advice. A restrictive diet should be discussed with a qualified healthcare professional to ensure it is safe and nutritionally adequate for you.
Blood Tests
Blood tests can measure both DAO and histamine levels, although results need to be interpreted by a qualified healthcare professional and are not enough on their own to confirm histamine intolerance.
A Practical DAO Trial
If DAO testing is not available where you live, some people consider trying a DAO supplement with meals while tracking their reactions. Any improvement might suggest that histamine metabolism is involved, but it does not diagnose a DAO deficiency. Discuss supplements with a qualified healthcare professional before trying them.
It is important to remember that each person has their own tolerance level, which may also be affected by outside factors such as seasonal changes. If you have allergies, or notice that symptoms become worse during seasonal transitions, histamine may be one factor worth discussing with a qualified healthcare professional.
Histamine and Hidradenitis Suppurativa
We are all familiar with the key symptoms of HS, which can include acute and chronic pain, discomfort, and purulent, unpleasant-smelling drainage. Together, these symptoms can significantly affect quality of life.
Hidradenitis Suppurativa and Itching
Earlier clinical studies focused mainly on these well-known symptoms, while less was known about itching. In 2011, a small qualitative study involving interviews with 12 people with HS found that itching, as well as drainage, pain, and scarring, had a significant psychosocial impact.
Histamine may be one of several factors involved in itching. Some members of our Facebook group have reported that their itching improved while following a low-histamine diet. These are personal experiences, not proof that the same approach will work for everyone, although limited studies in people with HS have also explored itching and related mechanisms.
At the moment, it is still unclear to me whether histamine affects abscess formation or other symptoms related to Hidradenitis Suppurativa. I searched extensively online but did not find clear evidence. We do know that histamine is connected to mast cell activity, which can in turn influence regulatory T cells. More broadly, research has linked histamine signaling with autoimmune processes, but HS is generally understood as an autoinflammatory condition, and this does not establish that histamine causes HS or its lesions. HS has no definitive cure, and dietary changes should not replace care from a qualified healthcare professional.
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