Histamine intolerance is a condition where there is an over-accumulation of dietary histamine in the human body. It is not a sensitivity to histamine but an indication that you have developed too much of it. Histamine is a chemical that is responsible for several major functions in the body, including sending messages to the brain, triggering the release of stomach acid to help digestion, and releasing after injury or allergic reaction as part of your immune response. When there is too much histamine, or it cannot break down properly, it can affect regular bodily functions.

Symptoms of histamine intolerance are nonspecific and can appear like symptoms of other conditions, which can make it challenging for doctors to diagnose. Gastrointestinal (GI) symptoms are the most common and include digestive issues, abdominal pain, bloating, diarrhea, constipation, flatulence, nausea, and vomiting. Other common reactions associated with this intolerance include headaches or migraines, nasal congestion or sinus issues, fatigue, itchy skin, hives, and irregular menstrual cycles. In more severe cases of histamine intolerance, you may experience abdominal cramping, tissue swelling, high blood pressure, and bronchospasms.

Histamine intolerance can happen if your body cannot break down histamine properly, causing histamine levels in the blood to rise. Many foods and drinks contain histamine, and some medications can affect how the body metabolizes histamine. Some examples of these drugs include antiarrhythmics, antihypertensives, muscle relaxants, narcotics, local anesthetics, and nonsteroidal anti-inflammatory drugs (NSAIDs) . High alcohol consumption and health conditions that damage the lining of the gut can also lead to histamine intolerance.

If you suspect that you have a histamine intolerance, your doctor might recommend that you avoid foods high in histamines to see whether it helps alleviate your symptoms. Histamine tolerance can vary greatly from person to person, and an elimination diet may be recommended to determine which foods your body can tolerate and which foods result in symptoms. Medical professionals often diagnose histamine intolerance after ruling out other conditions with similar symptoms.