Histamine Intolerance

This is an image of a person with histamine intolerance and its something I see regularly in my clinic.  Itchy skin and when scratched it leaves marks for some time. It can also appear as an itchy neck, rosacea, flushed and broken capillaries in the cheeks, itchy or dandruffy scalp, nasal allergies to room fragrances, perfume etc.

SO WHAT IS HISTAMINE? Histamine is a normal by-product produced by the body BUT if you are genetically predisposed to not having enough DAO (the enzyme that breaks it down) or you have overgrowth of bad microbes in your gut, or a sluggish liver, the excess histamine cant get out! Too much histamine then comes out in the skin as itchy rashes because it cant get out any other way!

3% of the population have poor histamine metabolism.

Seasonal allergies.

Patients may have childhood history of eczema, bad reaction to insect bites and a bit of rosacea in the face as they get older.

Histamine in the body also affects our circadian rhythm so often patients become insomniacs.


Increased Heart rate. Low Blood pressure.

Runny Nose. Sinus issues. Conjunctivitis

Brain fog and fatigue is common in histamine intolerances because when your immune system is on red alert like that the whole time it’s exhausting.

Sneezing upon “eating something” can trigger the mast cells to produce a histamine reaction.

Women with persistent interstitial cystitis may have histamine intolerance.

Swelling in the body may be histamine intolerance. Painful periods.

Alot of healthy foods contain histamine like Spinach, Tomatoes, Dried fruits, Aubergines, Avocado. Often the healthier the diet the worse the symptoms!

In interstitial cystitis this these colonies actually become part of the bladder wall and generally people who have histamine intolerance have thickened bladder walls so are more prone to this.

If you have IBS symptoms and rashes it can be a sign of Histamine Intolerance as dysbiosis in the gastroinstestinal tract can cause histamine may build up there. Even mild IBS with chronic headaches can be a sign.

Also during perimenopause oestrogen is fluctuating wildly. Your mast cells are covered in oestrogen receptors. So this is some of the reason why women in their late 30s, 40s and 50s get more skin issues that their younger selves because the mast cells are firing more and more histamine due the fluctuating oestrogen levels.

HOW DO I Diagnose HISTAMINE INTOLERANCE- Your GP can send out for it. A referral letter from gut health practitioner, dermatology, functional medicine can also order it. It can be treated on symptoms alone. Without a test.


Anti histamine medication like cetirizine and loratadine prescribed three times a day but at least twice a day can be helpful. You can buy over the counter. In some patients they are game changers and in some patients they make no difference at all. No major research is done yet and the full picture of these genetic mutations in susceptible individuals is also not yet available.  Dermatographic uticaria (itchy skin or hives like) should settle within 2 weeks of anti histamines.

Other treatments for getting histamine levels down in your body are taking the medical device Toxaprevent from Nhinnovations daily for 6 months. I can give you a discount code for this.

Taking a supplement called Quercetin is useful for calming the mast cells down (there the cells that produce histamine).

If you are then eating a lot of high histamine foods that can cause issues because you’re just overloading a system, that’s already overloaded. Many of the patients have normal histamine metabolism but there’s just too much histamine for the body to cope with. Some 3% of the population at least will have poor histamine metabolism in which case it’s double whammy for them so they’ve got too much histamine production so they’re going to have more inflammation so having a low histamine diet for everybody is helpful.

Doing a low histamine diet is very restrictive and not practical. So often the healthier the diet the worse the skin issues are! Alot of healthy foods contain histamine like Spinach, Tomatoes, Dried fruits, Aubergines, Avocado, Aged Meat or Fish or anything thats been dead a day or so. Unless the fish was caught that day! Or literally frozen or sold on the day of slaughter! Kefir or yoghurt, kombucha, kimchi, or any of the fermented foods are all high in histamine. You would need to know your butcher really well to get really fresh and lovely and tender meat. Also Salamis, Cheese, Fermented Dairy. Swelling in the body may be histamine intolerance. If you stop histamine containing foods the fluid should fall out of you.

Investigate whether you have overgrowth in the gut.  SIBO causes inflammation in the gut which can result in leaky gut long term, so toxins and food enter the blood stream and the mast cells go overboard reacting producing histamine and alterating the microbiome.

If in midlife and having symptoms of perimenopause maybe considering HRT to balance hormones.

If you stop histamine containing foods and no real improvement in symptoms then the patient should be investigated for Mast Cell Activation Syndrome (MCAS). I did a treatment protocal for 1.5 years for MCAS as part of getting to the root cause of my gut health struggles.