Histamine is a naturally occurring chemical that has many effects in the human body, including an important role in allergies. In a person with an allergy, the immune system responds to their allergen by releasing histamine, which causes various symptoms depending on the location. For example, in someone that has hayfever, exposure to pollen causes the release of histamine, which produces symptoms of an itchy, runny nose, with congestion and sneezing. However, sometimes histamine can produce allergy-like symptoms in the body that are not due to an immune response. These symptoms are the result of histamine intolerance.

The symptoms of histamine intolerance

Histamine has many functions and is found in nearly all the body’s tissues. Therefore, the symptoms of histamine intolerance are many and varied. These symptoms can be mild to severe, but they don’t all occur in the same person.

It is also important to remember that all of these symptoms can be due to other causes, including some that are potentially serious. So histamine intolerance should be considered as a possible cause of these symptoms only after other causes have been ruled out.

Respiratory system

• nasal obstruction or congestion
• runny nose, sneezing
• difficulty breathing, asthma attack

Cardiovascular system

• high blood pressure, or low blood pressure
• irregular or rapid heart rate, pounding heart
• weakness, fainting
• vertigo

Nervous system

• headache or migraine
• dizziness
• anxiety
• disturbance of the sleep/wake cycle, difficulty sleeping
• poor regulation of body temperature, or food intake
• memory problems, brain fog
• fatigue, confusion, irritability

Skin

• itchy skin, (can also affect eyes, ears and nose)
• flushing
• urticaria or chronic hives
• eczema

Gastrointestinal system

• nausea or vomiting
• diarrhoea or constipation
• reflux
• stomach ache, abdominal cramps
• excessive intestinal gas, bloating
• alcohol intolerance

Gynaecological

• painful periods
• premenstrual headaches or premenstrual migraines

All of these symptoms can be caused by having too much histamine in the body. And, I am going to discuss how that might occur in a future post.