Histamine intolerance occurs when there is a high level of histamine in the body, which can happen if the body cannot break down histamine properly. The impairment of gastrointestinal (GI) histamine degradation causes functional, nonspecific, non-allergic GI complaints and extra-intestinal complaints. The term “histamine intolerance” is used similarly to lactose intolerance (LIT) . The following are some of the causes of histamine intolerance:

• Deficiency of the gastrointestinal enzyme diamine oxidase (DAO): This is the most common cause of histamine intolerance. DAO is responsible for breaking down histamine in the gut. A deficiency of DAO can lead to an accumulation of histamine in the body.

• Ingestion of histamine-containing foods: Histamine is produced by bacterial fermentation and is found in many foods, including fermented foods, aged cheeses, cured meats, and alcoholic beverages.

• Health conditions that damage the lining of the gut: These conditions can lead to histamine intolerance by reducing the bodys ability to break down histamine.

• Certain medications: Some medications can affect how the body metabolizes histamine, leading to an accumulation of histamine in the body. Examples of such medications include antiarrhythmics, antihypertensives, muscle relaxants, narcotics, and local anesthetics.

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, one may experience abdominal cramping, tissue swelling, high blood pressure, and narrowing of airwaves, known as bronchospasms.