Histamine Intolerance

What is histamine intolerance?

Histamine intolerance (HIT) is a proposed condition caused by an inability to digest histamine in your diet, leading to gastrointestinal and allergy-like symptoms. Histamine is a chemical your body naturally makes. It’s also present in some foods. The American Academy of Allergy and Immunology doesn’t currently recognize histamine intolerance as a condition. It’s a controversial issue.

Some experts suggest that if your body can’t break down histamine as well as it should, it can build up in your body and cause symptoms. But a 2023 study ruled out histamine intolerance in most people who thought it was causing their symptoms. The study’s authors and other experts suggest that other conditions cause symptoms that look like a histamine reaction. So it’s important to speak to your healthcare provider if you have concerns about HIT.

Is histamine intolerance a food allergy?

No, histamine intolerance isn’t an allergy, even though some think it shares symptoms of allergic reactions. It’s sometimes called a “pseudoallergy” since it looks similar to an allergy but has a different cause.

Is this the same as histamine intoxication?

No, histamine intoxication (also called histamine poisoning) usually happens as a food poisoning outbreak, affecting many people who ate the same high-histamine meal. Public health officials usually trace it back to certain types of fish.

Histamine intoxication is well-documented. But histamine intolerance is more controversial. Experts disagree about whether relatively low levels of histamine could cause symptoms, or if it’s more likely that irritable bowel syndrome or another condition causes symptoms that look like HIT.

What are the symptoms of histamine intolerance?

The symptoms of histamine intolerance are different from person to person. You may have one or more of these symptoms:

• Diarrhea.
• Bloating.
• Nausea or vomiting.
• Headache.
• Runny or stuffy nose.
• Shortness of breath (dyspnea).
• Itching.
• Rash or hives.
• Flushing.
• Low blood pressure.
• Irregular or fast heart rate (arrhythmia).
• Painful menstruation.
• Swelling of your lips, tongue or throat.

What causes histamine intolerance?

According to some theories, histamine intolerance symptoms may happen when your body can’t break down histamine. Histamine is a chemical signal that opens up your blood vessels, constricts your airways and gastrointestinal (GI) tract, and creates mucus. Mast cells in your mucous membranes release histamine and other chemical signals to help fight infections and regulate your organs.

Your body uses enzymes, mostly diamine oxidase (DAO), to break down histamine. Some people speculate that reduced activity or low levels of DAO causes HIT. But this hasn’t not been scientifically validated. Experts aren’t really sure what would cause some people to have low levels of DAO or an inability to break down histamine as they should.

What foods trigger histamine?

Some foods contain large amounts of histamine. These include foods that involve an aging or fermentation process like wine, beer and cheeses. Other foods can cause your mast cells to release histamine (histamine liberators). Both of these types of foods can cause excess amounts of histamine in your body.

Some examples include:

• Alcohol (wine, beer and champagne).
• Processed meat.
• Cheeses.
• Sauerkraut.
• Vegetables (tomatoes, eggplant and spinach).
• Tropical fruit (pineapple, bananas, papaya and citrus fruits).
• Fish (mackerel, tuna, sardines and herring) and shellfish.
• Strawberries.
• Nuts and peanuts.
• Licorice.
• Chocolate.
• Pork.
• Egg white.
• Additives (like colorants and preservatives).

How is histamine intolerance diagnosed?

Not all providers recognize histamine intolerance as an official diagnosis, and there aren’t any proven ways to diagnose HIT. A provider can listen to your symptoms and may suggest looking for other possible causes. You may be referred to an allergy or GI specialist.

Your provider may order various tests or procedures to help make a diagnosis. These include:

• Food diary. Keeping track of your symptoms and what you eat and drink can help you identify if a food intolerance might be causing your symptoms. Sometimes it’s a combination of foods, beverages or medications taken together that are the problem. Keeping a diary helps patterns emerge that you might not have noticed before.
• Allergy skin tests or blood tests. These can help you identify or rule out food allergies.
• Food challenge. Your provider may have you eat a food of concern in the office and monitor you for symptoms.

How do you treat histamine intolerance?

Treatment for food intolerances usually involves avoiding foods or beverages that cause your symptoms. To test what you can safely eat, you stop eating any possible triggers for a few weeks. If you haven’t had symptoms in that time, you start adding them back in one by one. If you start having a reaction to certain foods or combinations of foods but not others, you can avoid only the ones that make you react.

Medications for histamine intolerance

A provider may recommend medications that might help relieve symptoms in combination with changing what you eat. They may suggest:

• H1 and H2 antihistamines. These block histamine receptors in various parts of your body so histamine can’t activate them. Taking antihistamines alone probably won’t stop your symptoms, but it could help in combination with dietary changes. H1 histamine inhibitors include cetirizine, loratadine and fexofenadine. They usually treat allergy symptoms. H2 inhibitors include ranitidine and famotidine. They usually treat digestive symptoms.
• Mast cell stabilizers. Medications like cromolyn sodium prevent mast cells from releasing histamine. Some food components called flavonoids — like luteolin and quercetin — have a similar effect.

When should I go to the ER?

Go to the emergency room or call 911 if you have signs of anaphylaxis, including:

• Swelling of your lips, tongue or throat.
• Trouble breathing.
• Sudden drop in blood pressure (symptoms include weakness, dizziness, fainting and confusion).

Are there medications that can increase histamine levels?

Certain medications have the ability to potentially increase histamine levels in your body. These include some types of pain medications (opioids/narcotics) and contrast agents used in medical imaging.

What can I expect if I have histamine intolerance?

People with food sensitivities can usually manage their condition by changing their diet. In severe cases, taking medications can help. Sometimes the intolerance is temporary, and you can eventually go back to eating foods that you’d been avoiding.

When should I see my healthcare provider?

Talk to your healthcare provider if you have unexplained symptoms or you think you have a food intolerance or sensitivity. They can help you sort out whether it’s an allergy, intolerance or something else.

What questions should I ask my doctor?

It might be helpful to ask your healthcare provider:

• Is this an allergy or an intolerance?
• How can I identify my triggers?
• What should I do if I have a reaction?