Mold is a Major Trigger of Mast Activation Cell Syndrome

Mold is a Major Trigger of Mast Activation Cell Syndrome

WAIT! Before you get started, make sure to access your FREE guide to mold exposure HERE.

Mast cells are an important part of your immune system, without them you would never heal from an injury. However, there is a condition where they become overactive and cause serious problems in the body – this condition is called mast cell activation syndrome (MCAS).

Mast cell activation syndrome is different from mastocytosis because mast cells aren’t accumulating in various organs. With mastocytosis, there is a proliferation or growth of mast cells, like a cancer. Mastocytosis is also very rare and not usually triggered by an irritant.

On the other hand, MCAS is characterized by overactive mast cells. MCAS can be imagined as though something rubbed up against your mast cells wrong, causing them to become aggravated. Another important difference between MCAS and mastocytosis is that MCAS patients will often come up normal during lab work.

Many things can trigger MCAS, including:

  • Mold
  • Chemicals
  • Allergens
  • Viruses
  • Heavy metals
  • Toxins

From what I’ve seen in my practice and have heard from my colleagues, mold is probably the number one trigger of MCAS, followed by infections. Once these cells are activated they start pouring out all sorts of inflammatory agents, such as histamine, and cytokines.


Beyond Histamine

Up until recently, when anything to do with mast cells where mentioned, histamine was the main inflammatory mediator that came to mind. However, we’ve come to realize that histamine is a very small part of the story.

Hundreds of chemicals have been associated with mast cells and they all have different actions in the body. Mediators include:

  • Histamine
  • Cytokines
  • Interleukins
  • Prostaglandins
  • Chemokines


Symptoms of MCAS

Currently, the most common illness associated with mold is chronic inflammatory response syndrome (CIRS) but we are finding MCAS is another disease often triggered by mold exposure. Similar to CIRS, MCAS has widespread symptoms that affect nearly every system of the body. This adds to the difficult nature of diagnosing MCAS properly.

Here some of the most common symptoms of MCAS:

  • Fatigue
  • Poor memory
  • Brain fog
  • Inability to focus
  • Mood disorders
  • Migraines
  • Rashes
  • Hives
  • Low blood pressure
  • Heart racing
  • Becomes lightheaded when they stand up quickly
  • Diarrhea
  • Abdominal pain
  • Constipation
  • Nausea
  • Bloating
  • Strong PMS symptoms
  • Allergy-like symptoms
  • Asthma
  • Wheezing
  • Shortness of breath

It's a common misconception that patients with MCAS have skin problems as the primary symptom. The number one sign of MCAS are neurological symptoms. However, they may also have skin reactions especially if there are a mold patient. Most of my mold patients have hives, flushing, and other skin reactions. This is especially true if they are coming in direct contact with mold or if they are detoxing from mold.

It is possible for a patient with CIRS to also have MCAS. You can tell this is happening when CIRS is correctly and systematically treated, yet the patient doesn't get well. This is when doctors tend to notice things like flushing and rashes, which are all signs of classical histamine reactions.

Histamine is problematic because it causes blood-brain barrier permeability and gut permeability. Usually, this is accompanied by food allergies and sensitivities. Chronic conditions such as MCAS are inherently complex, this makes diagnosis a process of elimination.

When I see suspected MCAS patients, we have to systematically work through multiple potential diagnoses until we rule out each disease individually. Ultimately, we come to the conclusion that they are struggling with MCAS by ruling out other possibilities.


My Personal Experience with Mold and Mast Cells

In 2014, my office flooded and we had massive mold issues which I didn't realize for several months. When I realized, I implemented the Shoemaker Protocol immediately. I started taking binders, used other detox methods, and removed myself from the mold exposure.

Shortly after, my body broke out in very severe hives. I took an anti-histamine to deal with the hives but realized what was happening was a massive mast cell activation in detox. My body was detoxing from mold through my treatments and by removing myself from the exposure, but it was causing mast cell activation symptoms. I experiences brain fog, respiratory issues, gastrointestinal distress, and my skin was covered in hives.

I've experienced firsthand mast cell activation – it can be very scary. What this means for me is that my body is going to continue to be more sensitive to environmental changes and toxin exposures than the average person. I am more prone to getting hives to exposures like VOCs and other triggers. While this is somewhat unfortunate, there is a lot that can be done for MCAS. Though MCAS treatment does require vigilance, it is possible to live a relatively normal life.


Biomarkers for MCAS

Though there is no definitive test for MCAS there are numerous tests you can combine to  support your diagnosis. In the figure below, you'll find the most common biomarker testing recommended for those suspected of having MCAS. There's no one lab that does all of these tests, you'll need to use both LabCorp and Quest.

When it comes to MCAS that's triggered by mold, there are few biomarkers that are more common than others. These include:

  • MMP – 9
  • C4a (C4b is usually seen  bacterial trigger)
  • TGF beta
  • VEGF

Also, you need to be sure that your doctor and the lab both know how to carefully handle samples for accurate results. Ultimately, blood test can't really confirm or deny the presence of an illness. The best way to know if you have MCAS or not, is by ruling out other illnesses through a comprehensive process of elimination. Lab testing helps this process but it’s not the full solution.

Slide credit to Dr. Sandeep Gupta with Mold Illness Made Simple


MTHFR status and MCAS

When people have MTHFR, A1298C and C677T, They have impaired methylation.  If they don't have enough active methylfolate or active methyl B12 or P5P or Riboflavin they're prone to have problems with methylation. This is especially important with anyone suspected of having MCAS,  

Because methylation is one of the most important pathways our body uses to break down histamine.

In the situation where a patient has impaired methylation, deficiencies and B vitamins, and the MTHFR genetic mutation,  this can complicate problems with excess histamine in the body. This is because the body is unable to break down histamine  well. If I find a patient is positive for the MTHFR status, we can add methyl B12 and methylfolate.

Other ways the body breaks down histamine include the DAO and  MAO enzymes.


Reducing mold exposure is the name of the game

If you suspect you have CIRS or MCAS,  it's important to check for mold exposure.  without identifying mold exposure symptoms will only continue to get worse and treatments will be ineffective.  this may mean removing yourself from the water damage building.

However, even when you fully remove yourself from a mold exposure your mass cells still might remain active. This is because they need assistance to detox and to return to a stable state.


Treating MCAS

When it comes to treating MCAS  that's been triggered by mold, you must eliminate mold exposure. Imagine your MCAS like a bucket, the more factors you have contributing to your activated mast cells, the worse your symptoms are.

You need to reduce the number of factors contributing to your MCAS. This is what I mean when I say you need to reduce your toxin burden. You might be surprised at how big of a difference it can make to get yourself into clean air and eating clean food. I always recommend eating as organic as possible, using a water filter, and an air purifier.

At first I can feel overwhelming, but if you change a little at a time, eventually you can make the overhaul necessary to live a full and healthy life. My patients often asked me if everything needs to be done with a hundred percent accuracy. When it comes to mold you really do need to remove yourself completely from the mold filled environment. In other areas of your life you might not necessarily need to be as strict after a while. However, it pays to be as strict as possible when you’re working to stabilize your mast cells initially.

There are a number of supplements you can take to help MCAS, these include natural antihistamines and mast cell stabilizers.

    • Ascorbic acid
    • Quercetin
    • Omega 3s
    • Vitamin B6
    • Vitamin B12
    • Vitamin C
    • Glutathione
    • Turmeric
    • P5P
    • Diamine Oxidase enzymes (DAO)
    • Resveratrol
    • Methylfolate
    • Umbrellux DAO
    • Lactobacillus rhamnosus
    • Bifidobacterium spp

If you suspect you have mast cell activation syndrome, I recommend you find an experiences functional medicine doctor who you like working with and trust. Because working to get a chronic condition under control takes time and patience. The good news is – it is possible to live a full and healthy live with MCAS.



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5 thoughts on “Mold is a Major Trigger of Mast Activation Cell Syndrome

  1. Andrew says:

    Hey Dr. Jill,
    Thank you for another very informative article! Do you suspect that MCAS is at the core of many symptoms for people with CIRS WDB and Lyme? I have both and am finding that when my MCAS is being controlled well (which so far has consisted of treating parasites, viruses, and limiting mold exposure) that I begin to feel lightyears better. But when I slip up and the MCAS is less controlled, all of the symptoms seem to reappear (cognitive, body aches, digestive issues, etc.).

    This all makes me wonder if MCAS is at the core of these illnesses for many people and if the CIRS and Lyme just exasperate those MCAS issues. I’d love to hear you inclination on this.

  2. Stan says:

    hi Dr. Jill, very useful article. Being registered already, I can’t download the Exposed to mold – what next? guide. Maybe others encounter the same issue, please explain another way how to reach the guide.
    I suspect the MCAS and mold being the reasons for the sudden and ongoing trigger of so many and worrying health issues. The negligence of the “traditional” medics on them is equal to crime.
    Thank you for addressing wide spread and important health issues, and helping far beyond your practice.

  3. Jackie says:

    Great article! Thank you for sharing, Dr. Jill!

    I developed severe acne rosacea on my cheeks as a result of mold-induced histamine intolerance. It has been 1.5 years since I detoxed from the mold, and yet I still have the acne rosacea. The acne and HIT actually got worse the more I detoxed. I no longer have mold in my body, I eat a low mold diet, my CIRS labs look pretty good, and I have a high-quality air filter, yet my histamine intolerance never subsided. Any suggestions on where to go from here to address my skin? I am not currently taking H1 or H2 blockers but am considering trying to see if it would help – do you consider these safe to try in conjunction with more natural remedies?


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