Histamine intolerance is not a sensitivity to histamine, but an indication that you’ve developed too much of it.

Histamine is a chemical responsible for a few major functions:

  • communicates messages to your brain
  • triggers release of stomach acid to help digestion
  • releases after injury or allergic reaction as part of your immune response

When histamine levels get too high or when it can’t break down properly, it can affect your normal bodily functions.

Histamine is associated with common allergic responses and symptoms. Many of these are similar to those from a histamine intolerance.

While they may vary, some common reactions associated with this intolerance include:

In more severe cases of histamine intolerance, you may experience:

You naturally produce histamine along with the enzyme diamine oxidase (DAO). DAO is responsible for breaking down histamine that you take in from foods.

If you develop a DAO deficiency and are unable to break down histamine, you could develop an intolerance.

Some reasons your DAO enzyme levels could be affected include:

  • medications that block DAO functions or prevent production
  • gastrointestinal disorders, such as leaky gut syndrome and inflammatory bowel disease
  • histamine-rich foods that cause DAO enzymes to function improperly
  • foods that block DAO enzymes or trigger histamine release

Bacterial overgrowth is another contributing factor for developing a histamine intolerance. Bacteria grows when food isn’t digested properly, causing histamine overproduction. Normal levels of DAO enzymes can’t break down the increased levels of histamine in your body, causing a reaction.

Foods to avoid

A healthy diet contains moderate levels of histamine. However, there are some foods high in histamine that can trigger inflammatory reactions and other negative symptoms.

Histamine-rich foods are:

There are also a number of foods that trigger histamine release in the body, such as:

Foods that block DAO production include:

Foods to eat

If you have a histamine intolerance, incorporating low-histamine foods into your diet can help reduce symptoms. There’s no such thing as a histamine-free diet. Consult with a dietician before you eliminate foods from your diet.

Some foods low in histamine include:

Before reaching a diagnosis, your doctor will eliminate other possible disorders or allergies that cause similar symptoms.

Doctors may also suggest following an elimination diet for 14 to 30 days. This diet requires you to remove any foods high in histamine or histamine triggers, and slowly reintroduce them to watch for new reactions.

Your doctor might also take a blood sample to analyze if you have a DAO deficiency.

Another way to diagnose histamine intolerance is through a prick test. A 2011 study examined the effectiveness of a prick test to diagnose histamine intolerance. Researchers pricked the skin of 156 people and applied a 1 percent histamine solution. For those with suspected histamine intolerance, the prick test was positive for 79 percent, revealing a small red, itchy bump on the tested area that didn’t resolve within 50 minutes.

Histamine intolerance can cause uncomfortable symptoms, but it can be treated with a low-histamine diet.

Histamine intolerance shouldn’t be self-diagnosed since symptoms are similar to other allergens, disorders, or infections. If you think you might have an intolerance or are experiencing irregular symptoms, talk with your doctor.