what is mcas
This post provides a primer on what is MCAS, or Mast Cell Activation Syndrome.
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The following material does not constitute medical advice. This information is for information purposes only and is not intended to be a substitute for professional medical advice, diagnosis, cure, or treatment. Always seek advice from your medical doctor.
Mast Cell Activation Syndrome (MCAS) is a chronic condition that affects all organ systems. MCAS is serious and disabling and people with MCAS experience often significant and debilitating symptoms daily, including anaphylaxis, which can be fatal.
MCAS is often found in combination with other chronic conditions such as Ehlers-Danlos Syndrome (EDS) and Postural Orthostatic Tachycardia Syndrome (POTS).
Frequently healthcare providers do not know about MCAS, and the tests for MCAS are problematic because they are not uniformly reliable. MCAS can be difficult to manage. Treatments include blocking mast cell mediators with anti-histamines and mast cell stabilizers, as well as avoiding triggers.
Check out this post on how to manage MCAS
Mast cells are part of our bodies that cause immediate allergic reactions, and by releasing parts of their cells called “mediators” they cause allergic symptoms. This process works in concert with antibodies; the triggering is known as “activation.” When too many mediators are released the body begins to act as though it is under significant threat, though what is causing the release may be benign. For many people with Mast Cell Activation Syndrome, or MCAS (pronounced em-cass), normal healthy foods, environmental stimuli like scents, temperature variation, and even stress become triggers. When too many mediators are released allergic symptoms escalate leading to major allergic events and even anaphylaxis.
There are a number of issues that stand in the way of being easily diagnosed and treated for Mast Cell diseases. Part of the problem with having a Mast Cell disease (there are several) is that knowledge about them is not yet widely available. Where I live in Minnesota there are only two or possibly three knowledgeable providers who specialize in MCAS. Many functional providers know about it and can help with diagnosis and treatment. But there needs to be much more research and advocacy so that upcoming medical doctors know about (and don’t dismiss) Mast Cell diseases.
Mast Cell diseases can look like other diseases, and patients are often misdiagnosed for years before they finally figure out what is going on. The diagnostic tests for Mast Cell diseases are extraordinarily finicky, and many people are misdiagnosed due to faulty testing. And many uninformed providers suggest that patients stop taking the drugs controlling their symptoms prior to testing, which can cause catastrophic symptom flares.
The range of symptoms that can occur in Mast Cell diseases covers practice areas from hematology to dermatology to oncology to rheumatology, with many possible other areas. Because there is not one area of the body affected by Mast Cell diseases there is a tendency of medical providers to pass patients off to another provider who presumably knows more about it. But in reality, there are only a handful of providers who specialize in Mast Cell diseases in the US. To be properly diagnosed you need to travel to Alberta Canada, New York, and a number of other places. Here is another list of providers.
The Bucket Theory offers a helpful analogy for understanding symptom reactions with MCAS.
Think of your body as an empty bucket that you want to keep from overflowing. Different foods and activities fill your histamine bucket at different speeds but they combine to form the total level of histamine in your body (how full your bucket is). A fuller bucket means you have more histamine symptoms. When you manage triggers, reduce exposure to known triggers, and take medications and supplements to reduce histamine, you can manage the level of your bucket.
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One of the keys to understanding the level of your bucket is knowing your symptom progression. It is helpful to keep track of the symptoms you are having and to evaluate whether they are escalating. Symptom escalation means that the level of your bucket is rising.
Knowing your symptom progression in a symptom flare is the key to developing your own rescue plan. In this post, I discuss how to determine your own symptom progression. Once you know what typically happens in your symptom progression you can design a rescue plan to address those symptoms.
I’m not a health professional and I can’t begin to do justice to the intricacies of MCAS and other Mast Cell Diseases, but I have found some very good resources available to dig into it and read more:
The most common drugs that are prescribed for treating MCAS include:
Histamine 1 blockers – Hydroxyzine (Atarax), Doxepin (Silenor), Cyproheptadine (Periactin), Loratadine (Claritin), Fexofenadine (Allegra), Diphenhydramine (Benadryl), Ketotifen (Zaditen) and Cetirizine (Zyrtec, Reactine).
Histamine 2 blockers – Famotidine (Pepcid, Pepcid AC), Cimetidine (Tagamet, Tagamet HB), and Ranitidine (Zantac). Famotidine is chosen most often because it has fewer drug interactions than Tagamet.
Mast Cell Stabilisers – Cromolyn (Cromolyn Sodium, Gastrocom—oral form, Nasalcrom—nasal spray, Opticrom—eye drops, and there is a nebulized form and a cream can be made from a bottle of Nasalcrom and Eucerin or DMSO cream), Ketotifen (both a mast cell stabilizer and an H1 blocker) and Hydroxyurea (Hydrea).
Mast Cell Inhibitors – Montelukast (Singulair), Zafirlukast (Accolate), and Zileuton (Zyflo). Pentosan (Elmiron) is used in the genitourinary tract for perineal pain and interstitial cystitis.
And here is a list of common supplements that are helpful in treating MCAS:
Mast Cell triggers can include:
So, you can see that MCAS can be extremely pervasive, affect multiple body systems, and be frustrating to diagnose. It can take exhaustive tracking of diet and possible environmental triggers to figure out what your personal triggers are. What is triggering to one person may not be for someone else. And what triggers a symptom flare today may not trigger one tomorrow in the same person, because variables such as past triggers and level of activation play a role.
Here is an example. On Saturday I was outside for part of the day at my son’s Ultimate Frisbee tournament (pollen, heat, sun, dehydration); I came home and mowed the lawn (fatigue, pollen, sun, heat, dehydration); and then I went out for a special anniversary dinner and splurged on a few foods that I know are ordinarily triggering (crab, spices). I took about five extra doses of my mast cell stabilizers over the evening and one extra Claritin, and I didn’t react.
After all of those triggers the previous day, I went to the second day of my son’s tournament (pollen, heat, sun, dehydration); for dinner, I ate one possibly triggering food and started to experience my symptom progression of facial flushing, allergy symptoms, and sciatica. See my post on knowing your symptom progression.
The Bucket Theory offers a helpful analogy for why this happens. “You could think of your body as an empty bucket. Different foods and activities fill your histamine bucket at different speeds but combine to form the total level of histamine in your body. If you can keep your bucket at a lower level, you may feel better because a fuller bucket could mean you have more symptoms. Managing triggers, reducing exposure to known triggers, and taking medication could all help to manage the level of your bucket.”
So, likely my bucket was still full from Saturday when I had that one possibly triggering food that overfilled my bucket. The result was a pretty bad reaction.
Yet, histamine is not the only mediator that can affect Mast Cells. Others are:
As I discuss in my second book, and in episode 47 of the Miracle Voices Podcast, both of my daughters have Mast Cell Activation Syndrome (MCAS), though one of them also has disabilities from a neurological disorder. I was my disabled daughter’s full-time caregiver from 2016-2022. In 2020 I experienced a health crisis and realized that I must also have MCAS. The stress of the pandemic, mold exposure, Lyme Disease, moving houses, and long-term caregiving became triggering events that pushed my body from being able to manage occasional triggers, to entering a period of free fall as symptoms that had somehow been suppressed for years went out of control.
Within three months I had to eliminate 75 percent of the foods in my diet because I suddenly could not tolerate them. I was alarmed to need more and more antihistamines to remain stable, and the things I had taken for granted – my toothpaste, my favorite foods, my essential oils, and dozens of other things – had to be discontinued to arrest the cycle of Mast Cell over-activation.
With the help of my functional medicine provider, my MCAS symptoms have been somewhat under control with a daily intake of an H1 blocker (Claritin), Quercetin (a flavonoid which is a mediator blocker), Vitamin C (an antioxidant), Curcumin (an anti-inflammatory), PEA (an endocannabinoid-like lipid mediator with extensively documented anti-inflammatory, analgesic, antimicrobial, immunomodulatory and neuroprotective effects), D-Hist (a targeted blend of flavonoids, antioxidants, proteolytic enzymes and botanicals to support allergies), Histamin Block (an enzyme formula that replenishes DAO in your gut), and NAC (an antioxidant). But I was still experiencing symptom flares several times a week because my bucket was still too full.
I experienced a big breakthrough though when I added Luteolin (another flavonoid that is a mediator blocker) daily with each meal. Suddenly I could tolerate many more foods, and my reactions were less severe.
This is a big topic, so I think I will stop here for now! I will post about some of the intricacies of managing MCAS in future posts. So stay tuned!
Do you have MCAS or histamine intolerance? I’d love to know what you think of this post! Please comment below!
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