An Herbal Approach to MCAS and Histamine Intolerance

I always tell my patients with histamine issues, whether it’s histamine intolerance or mast cell activation syndrome (MCAS), that they are “the canary in the coal mine.” The canaries were the warning sign, just like people with easily-angered mast cells warning us that our environment is changing, our genes are becoming more sensitive to pollution, and our physiology is losing its resilience to stressors of daily living. However, there is indeed hope and healing – the body can be retrained and herbal medicine offers a set of tools to help it do just that!

Mast Cell Activation Disorder (MCAD) is an umbrella term for mast cell conditions that results in either the overproduction of mast cells or overactivation of existing mast cells^1,2,3,4. Mastocytosis is an extremely rare type of MCAD, which results in abnormal accumulations of mast cells in the skin, bone marrow, and organs⁵. Mast Cell Activation Syndrome (MCAS) is another type of mast cell disorder, which is characterized by a variety of health concerns due to the multi-system impact of mast cell mediators, including but not limited to histamine, heparin, cytokines, and numerous proteases⁶. Both conditions (mastocytosis and MCAS) can result in anaphylactic responses, which tend to be much more severe in mastocytosis.

Conversely, histamine intolerance is believed to result from the over-accumulation of histamine and/or poor histamine catabolism⁷. These patients can have very similar complaints as MCAS patients, however they are not as severe, long-lasting, and more easily addressed once the appropriate diagnosis is made.

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Common symptoms of both conditions include poor digestion, food sensitivities, chemical/environmental sensitivities, pruritus, brain fog, urticaria, hypotension, tachycardia, anxiety, depression, and chronic fatigue. (Please see the references for a more expansive symptom list and work-up.)

Scutellaria Baicalensis (skullcap) — Scutellaria baicalensis (skullcap)

MCAS patients often benefit from strong immune modulators, nervous system trophorestoratives, and mucilagenous herbs that soothe and heal the GI system. Immune modulatory herbs serve to “retrain” a hyper-reactive immune response. In MCAS, patients either produce too many mast cells or trigger the ones they have more readily. The clinician must determine what each patient’s triggers are and address each of those as well. Inflammation modulators like Curcuma longa (Tumeric), Boswellia serrata (Frankincense), and Scutellaria baicalensis (Skullcap) aid in immune cell regulation, helping to retrain the inflammatory cascade⁸.

It is interesting that many inflammation-modulating herbs also offer anti-allergic actions as well, for example, Curcuma longa has been shown to decrease symptoms of food allergies and inhibit mast cell release^9,10. And Scutellaria baicalensis has been shown to have anti-allergic effects and even be useful in allergy-induced asthma^{11, 12}. Nervous system trophorestoratives offer healing to the overtaxed system and a means to recalibrate the patient’s resilience to stress, which in turn, indirectly decreases mast cell reactivity. This is something I’ve found more beneficial clinically, rather than reflected in research. Some herbs to consider using include Avena sativa (Oat), Verbena officinalis (Vervain), and Matricaria chamomila (Chamomile). Lastly many of these patients struggle to eat a normal diet, often finding reactivity to a variety of foods. It becomes a challenge to heal their reactive GI system through dietary intake alone, thus, Althaea officinalis (Marshmallow) and Ulmus rubra (Slippery Elm) can be used to heal the irritated mucosa while providing some nutrition. Althaea has even been found to have anti-inflammatory effects in asthma¹³.

Urtica (nettles) — Urtica Diocia (nettles)

Patients with histamine intolerance can benefit from the aforementioned herbal actions, in addition to herbs with more targeted antihistaminergic and mast cell stabilizing properties. For example, Urtica diocia (Nettles) has been shown to positively impact the inflammatory cascade in allergic rhinitis¹⁴. And Nigella sativa (Black Cumin) has been found to have anti-inflammatory effects in asthma, as well as, shown to decrease mast cell release^15,16. Moringa oleifera (Moringa) has also been shown to inhibit mast cell release¹⁷. Urtica and Moringa can be easily made into teas and consumed throughout the day while Nigella sativa is best consumed as an oil or capsule (capsule preferred, as it has a strong taste).

Other considerations in treating these patients would be to improve their overall digestion, whether that is eliminating food allergens or offering botanical support (e.g. bitters) to stimulate production of digestive enzymes. For both MCAS and histamine intolerant patients limiting higher histamine-containing foods while retraining the system is often warranted. Even alcohol in tinctures can sometimes be a trigger for sensitive MCAS and histamine intolerant individuals, and glycerites, teas, or capsules should be used instead. However, while recommending diet changes, it’s important to foster a positive attitude toward food as many of these patients may become afraid to eat due to hyper-reactivity. Treating dysbiotic flora is also necessary, especially since certain bacteria have been associated with histamine intolerance and even inflammatory states in autoimmune disease^18,19.

While these patients’ symptom list and reactivity may seem daunting at first, understanding the underlying cause serves as a guide for appropriate botanical intervention. Start your patients slowly, reassure them as their body responds, and focus on the patient triggers so you know how to guide them back to optimal health.

For more on this topic, see part 2: Retraining the Mighty Mast Cells: Mast Cell Activation Disorder and Histamine Intolerance Revisited

Note: The information on this site is provided as a research resource for health professionals and is not intended to replace diagnosis and treatment by a qualified health care practitioner. Consult your medical care provider before using any herbal medicine.

Meet Our Contributor:
Allison Williams is a Naturopathic Doctor in Mesa, AZ. She practices family medicine with a focus on gastrointestinal health, women’s medicine, autoimmune disease, and she has a love for geriatrics. She teaches botanical medicine at SCNM where she is also a second year general medicine resident. Botanical medicine is one of her favorite modalities. You can find her at: drallisonwilliams.com.

Clarification: After the initial publication of this article, we discovered an error in the definitions of Mast Cell Activation Disorder (MCAD) and Mast Cell Activation Symdrome (MCAS). MCAS and mastocytosis are types of MCAD (which is the correct umbrella term for these conditions). We have corrected the article to reflect this. We regret the error.

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