Introduction
We are all familiar with allergies. This might be from sneezing, runny nose, itchy eyes as well as non specific red rashes. Some times this can come at unexpected times like in the shower, when going for exercise or a change in weather.
Histamine is one of the chemicals in the body behind allergies. It causes our skin to to get red, swollen and itchy and also causes sneezing and discomfort. At the same time, histamine can have other unwanted effects like causing stomach acid and trouble sleeping.
One major cause of histamine is an imbalance in the gut. We have trillions of good bacteria in our gut; if our diet and environment leads to the wrong kind of bacteria thriving, this can irritate our gut immune system leading to more histamine to be produced. By focusing on the gut we can help reduce histamine and clear it out of our system.
What is histamine?
Histamine is a chemical mediator of allergies. It can lead to:
- Hives (red itchy skin rashes)
- Itchy skin
- Asthma attacks
- Runny nose, sneezing and itchy eyes
- Life threatening allergic reactions called anaphylaxis
- Swollen lips
- Stomach acid
What leads to higher histamine?
Histamine is made and stored in a range of immune cells around the body. When these cells are triggered by an allergen or immune event, histamine can be released.
Histamine is produced in particularly high levels in the human gut; in the setting of a gut dysbiosis or infection which triggers histamine, a person can develop a range of histamine mediated symptoms such as recurrent hives, asthma attacks, itchy skin, sneezing. Low levels of chronic histamine release in the gut is often associated with symptoms of gut allergy, intolerance of heart burn or a total body sensation of fatigue and brain fog.
Local tissues in the body can also release histamine in response to a triggering event. This is often seen with hayfever or an allergic skin rash.
A dramatic case of histamine release is anaphylaxis, a life threatening illness caused by a severe and overwhelming release of histamine in response to a particular allergen. This can be life threatening and patients with this type of allergy need to carry adrenalin and be prepared to call an ambulance if it occurs.
Investigations for histamine disorders
If somebody is having recurrent histamine events, investigations should take place such as:
- Gut pathogen or parasite (such as Helicobacter pylori)
- Dysbiosis, or imbalance in gut bacteria
- Vitamin deficiencies
- DAO activity, an enzyme that is involved with histamine
- Blood tests such as IgE
- Allergy testing, such as skin prick test.
In a case of severe anaphylaxis or severe allergy, a patient should be referred to an allergy specialist to undertake testing to identify the cause of the allergy. This is necessary so that the trigger for any severe allergy can be identified and avoided. The prescription and education in using adrenalin or an EpiPen should also take place.
How is high histamine treated?
For patients outside of a clear and straightforward single point allergy, such as peanut anaphylaxis, the treatment of chronic histamine release involves multiple steps.
The first step is to resolve any underlying medical issues and remove any clear causes of high histamine (gut pathogen, house dust mite). Specific allergen desensitisation therapy may be required for some allergies.
Beyond this, a diet that excludes high histamine foods is recommended:
High Histamine Foods
- Alcohol
- Pickled or Canned foods (Sauerkraut)
- Matured cheeses
- Smoked meats
- Beans (chickpea, pulses, peanuts)
- Shellfish
- Chocolate/cocoa products
- Citrus fruits
- Vinegar
- Ready meals
Some other treatments include:
- DAO enzyme to help break down histamine
- Gut probiotics to lower inflammation at the gut level:
- Prebiotics such as modified citrust pectin or astragalus
- Vitamin C (ginger), Zinc, vitamin B’s, Quercetin, NAC
- Rhamnosus GG
- Quercetin, a natural herbal anti histamine
