Histamine intolerance is when the body can't process high levels of histamine, a chemical that causes runny nose, congestion, and other symptoms. While histamine is best known as the chemical the immune system produces in response to an allergic or inflammatory reaction, it also communicates important information to the brain and plays a role in digestion.
:max_bytes(150000):strip_icc()/GettyImages-1206837302-bcae6708402d4782a4a93ac42ef1c5c2.jpg "The Symptoms, Diagnosis, and Treatment of Histamine Intolerance (1)")
Histamine can be found in certain foods and some foods release histamine stored in the body. Diet alone can cause histamine levels to rise so high that someone with histamine intolerance experiences allergy-like symptoms without having an allergic reaction. It's also possible for someone to have allergies and histamine intolerance.
This article covers what it means to have histamine intolerance, how it differs from an allergy, and steps you can take to minimize your symptoms.
The Difference Between Food Allergy and Food Intolerance
Histamine Intolerance Symptoms
The most common symptoms of histamine intolerance include:
- Migraine headaches
- Digestive symptoms, such as diarrhea
- Flushed skin
- Hives or an itchy skin rash
- Worsening eczema, or a condition that causes itchy and flaky rashes
- Congested, runny, or itchy nose
- Red, itchy, or watery eyes
A histamine intolerance intolerance may look like:
- Flaky skin
- Red skin
- Raised, red, and warm bumps or welts
The severity of symptoms can vary from person to person.
Because levels of histamine can build up in the body, people who have allergies in addition to a histamine intolerance can experience more serious allergic reactions. These can include asthma attacks or even anaphylactic shock—a dangerous, rapid reaction that causes breathing issues and a life-threatening drop in blood pressure.
Elevated levels of histamine can also cause the heart to beat erratically and may be associated with serious chronic conditions like Crohn's disease.
What Causes High Histamine Levels?
Your body makes two enzymes in order to process histamine: diamine oxidase (DAO), which comes from the digestive tract, and histamine-N-methyltransferase (HNMT), which comes from the central nervous system.
Without enough of the right enzymes, most commonly DAO, to clear histamine from the body and maintain healthy levels, it can build up and cause symptoms that can mimic allergies.
Various circ*mstances can impact these enzymes and cause histamine intolerance symptoms:
- Genetics: Some people have genetic mutations that decrease the amount or function of DAO.
- Medications: Some medications such as blood pressure medication, antidepressants, and anti-vomiting drugs can affect the production of DAO or block DAO in the body.
- Diet: Foods that contain histamine can also contain substances that temporarily block DAO. Alcohol and certain drugs, including some blood pressure drugs and acid blockers, can also reduce the enzyme's activity.
- Gastrointestinal (GI) disorders: GI disorders such as inflammatory bowel disease, celiac disease, malabsorption, or gluten sensitivity can affect DAO levels.
Research has shown that a small portion of people—about 1% to 3%—have a histamine intolerance.
Allergy vs. Intolerance
An intolerance—to a food or a chemical—is different from a true allergy. An intolerance usually occurs when your body lacks certain enzymes needed to digest or process a substance. An allergic reaction occurs when your body's immune system identifies and attacks an allergen.
Diagnosis
Diagnosing a histamine intolerance can be challenging. Like other chemicals in your body, levels of histamine shift based on the speed at which your body processes it.
Eating a high-histamine food (or more than one at the same time) may be enough to cause symptoms one day, but may not be enough to do so on a different day.
Testing is needed to help form a diagnosis—a process that includes, and may even start with, taking steps to rule out other possibilities.
Review of Symptom History
If you repeatedly experience symptoms after eating foods that are high in histamine, it may be helpful to keep a food log and review it with your healthcare professional.
A record of the foods you eat and any symptoms you develop can help you and your medical professional track the pattern of symptoms and determine whether specific foods may be to blame.
Tests to Rule Out Other Conditions
Coming to a histamine intolerance diagnosis is often a process of elimination.
Traditional allergy tests are not effective for diagnosing histamine intolerance, however, your healthcare provider may use these tests to make sure specific allergens aren't causing your symptoms. These include skin tests that measure reactions when small amounts of allergens are injected or applied to small breaks (or pricks) in the skin.
Furthermore, studies have shown that histamine may play a role in inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS).
If you are experiencing gastrointestinal symptoms, such as diarrhea, your healthcare provider may run additional tests to rule these two conditions out.
These tests could include:
- Blood or stool tests
- Imaging, such as an X-ray or computed tomography (CT) scan
- Colonoscopy
- Endoscopy of the upper gastrointestinal tract
Colonoscopy: Overview
DAO Testing
A blood test to check your DAO levels may be useful, as it can determine whether they are too low.
Histamine Challenge
If a histamine intolerance is suspected, your healthcare provider may recommend a test called a histamine challenge.
For this test, you are given food that contains histamine to determine the threshold dose of histamine capable of triggering symptoms. This test demands supervision of specialists and is only offered in a few medical settings due to its complexity and potential serious side effects.
Histamine Intolerance Treatment
Like an allergy, the best way to naturally treat an intolerance is to avoid the substance—in this case, histamine. A histamine-free diet may be enough to make your symptoms go away.
While a histamine-free diet is the only true long-term treatment for histamine intolerance, there are a couple of other options that can help you manage symptoms. These may be particularly useful for those whose symptoms are frequent and severe.
How to Stop Histamine Naturally
Avoiding histamine-rich foods, or foods that trigger your body to release histamine, is an important first step. Maintaining a strict low-histamine or histamine-free diet is the key to relief from histamine intolerance symptoms.
Research suggests that pediatric patients who tried a low-histamine diet over a four-week period saw an average of 88% to 100% reduction in their symptoms.
Your healthcare provider may also recommend certain supplements.
Diet
Your healthcare provider will discuss which foods you should avoid. In general, fermented, aged, or processed foods have higher levels of histamine and are more likely to cause problems. Other foods, such as citrus fruits, can trigger your body to release stored histamine.
Alcoholic beverages can be problematic for people who have histamine intolerance because alcohol can make DAO less effective. Therefore, giving up alcohol is part of a histamine-free diet strategy.
High-Histamine Foods
Aged cheeses (like Parmesan)
Avocado
Beer
Processed meats (e.g., cold cuts, hot dogs)
Sauerkraut
Spinach
Wine (especially red)
Foods that Release Stored Histamine
Chocolate
Citrus fruits
Nuts
Pineapple
Shellfish
Strawberries
Tomatoes
What Is a Low-Histamine Diet?
Supplements
In addition to a modified diet, your healthcare provider may recommend using certain types of supplements, such as a DAO supplement, to help naturally reduce or eliminate your symptoms.
They may also suggest a strong, natural antihistamine like vitamin C, as well as copper, or vitamin B6. These all naturally stimulate the activity of histamine-processing enzymes in the body.
Talk to your healthcare provider if you're interested in trying these supplements to see whether they could improve your symptoms.
Natural Antihistmamines
Medications
Antihistamine medicines, such as Benadryl (diphenhydramine), may be useful if you accidentally eat a food that contains histamine. These medications block histamine activity and can reduce symptoms.
There are multiple antihistamine medications available over the counter or by prescription. Many have potential side effects that can include drowsiness, headache, constipation, and dry mouth.
Talk to your healthcare provider about which antihistamine is best for you.
Changes to Current Medications
Talk to your healthcare provider about any medications, prescription or non-prescription, you're already taking. Some medications can affect the action of your histamine-processing enzymes.
If you are taking such a medication, your healthcare provider may adjust your dosage, switch you to a similar medication that doesn't affect histamine, or take you off the medicine entirely if it's safe to do so.
Antihistamines and How They're Used
Summary
If you frequently experience allergy symptoms after consuming high-histamine food and drink like beer or wine, sauerkraut, or even certain cheeses, it's possible that you may have an intolerance to histamine instead of a food allergy.
The best way to naturally treat a histamine intolerance is avoidance. By not eating foods that contain histamine or prompt your body to release it, you can take control of your symptoms. Talk with your healthcare provider about whether you should also consider an antihistamine medication or an enzyme-boosting supplement.
