Mast Cells and Mast Cell Activation Syndrome 101 What to know if you have Mast Cell Activation Syndrome or Histamine Intolerance

Mast Cells and Mast Cell Activation Syndrome 101: What to know if you have Mast Cell Activation Syndrome or Histamine Intolerance

In this blog post, we’re getting back to the basics on Mast Cells, Mast Cell Activation Syndrome, and even a little about Histamine Intolerance.

I hope this will help you understand Mast Cells, Mast Cell Activation Syndrome, and Histamine Intolerance better.

Even if you’ve been following Mast Cell 360 for a while now, this should be a good refresher. I pick up new insights each time I hear something a second time. I hope you will, too!

We’ll start by talking about what mast cells are. We’ll also cover what they do.

Like always, this blog post is for educational purposes only. It is not meant to treat, diagnose, or prevent illness. Always make sure to work with your healthcare provider.

Okay, let’s get back to the basics…

What are Mast Cells? – What to Know for People with Mast Cell Activation Syndrome and Histamine Intolerance

What are Mast Cells Mast Cell 360

So, what are mast cells?

Mast cells are specialized immune cells. They are part of our frontline sensors and defenders. They have many important roles in the body. One major one is that they respond to toxins and pathogens.

Pathogens can be things like bacteria and viruses. Toxins can be things like mold or chemicals.

I like to say the mast cells are one of the major conductors of the immune system.

And mast cells are also involved in our response to our environment. Think: heat, cold, light, sound, touch, smell… Basically, mast cells respond to anything involving our five senses.

They are also part of repairing injury. And mast cells are involved in a lot of other actions in your body as well!

Mast Cells are found in almost every tissue in the body.

Here are the main categories of mast cell locations:

  • Mucous and lining tissues:
    • the lining of the nose and sinuses
    • lining of the eyes
    • lining of the mouth
    • lining of the entire digestive tract
    • lining of the bladder and urethra
    • lining of the lungs
  • Blood vessel and cardiovascular tissues:
    • arteries and veins
    • capillaries
    • heart
  • Connective tissues:
    • ligaments
    • tendons
    • bones and bone marrow
    • joints
    • the lymph system
    • hair follicles
    • skin
  • Nerve tissue and parts of the brain

They are found nearly everywhere except the spinal cord and retina.

When I was really sick, even my hair follicles hurt. It was a light bulb moment for me when I realized that Mast Cell Activation Syndrome was behind this! 

See, when mast cells are triggered, they produce inflammation. Even in hair follicles!

Now you know a little about what mast cells are. Next let’s look at their roles and functions.

Roles and Functions of Mast Cells --What to Know for People Who Have Mast Cell Activation and Histamine Intolerance

Mast Cell Activation Syndrome MCAS Beth O'Hara Genetics

Mast cells have so many different functions in the body. This is why I really focus on them.

Here are some of the mast cell roles and functions in the body:

  • Immune function

  • Defending against infections: like viruses, bacteria, mold, candida, and parasites

  • Venom detoxification: Bee sting, mosquito bite, spider bite, snake bite

  • Wound healing and tissue repair

  • Helping build new blood vessels + widening blood vessels – This tends to lower blood pressure

  • Balance tissues and organs

  • Supporting brain function + creation of new brain cells

  • Regulation of the menstrual cycle

  • Pregnancy – support fetal growth and placenta

You can see they have an impact on a lot of different systems and processes. So, it’s important that our mast cells stay happy and in balance!

But problems can occur with mast cells sometimes. Sometimes there are abnormally high levels of mast cells from genetic issues. This is called mastocytosis. It’s fairly rare.

Problems can also occur when the Mast Cells become over-reactive and over-sensitive. This is called Mast Cell Activation Syndrome. And it’s extremely common.

Mast Cell Activation Syndrome happens when Mast Cells become over-reactive and over-sensitive.

Mast Cell Activation Syndrome occurs in 10-17% of the general population. And well over 50% of those with chronic health issues.

So, the mast cells aren’t the bad guys. They are very important in your body! It’s what is making them triggered that’s the problem.

So what makes mast cells hyperresponsive?

We’ll look at that next. Let’s first look deeper at what is happening with these Mast Cells in Mast Cell Activation Syndrome.

Below is a diagram of a mast cell. It’s from a study published in 2017.

Mast Cell Receptors

Image source: Spoerl, D., Nigolian, H., Czarnetzki, C., & Harr, T. (2017). Reclassifying Anaphylaxis to Neuromuscular Blocking Agents Based on the Presumed Patho-Mechanism: IgE-Mediated, Pharmacological Adverse Reaction or “Innate Hypersensitivity”?. International journal of molecular sciences, 18(6), 1223. https://doi.org/10.3390/ijms18061223

This picture shows that your Mast Cells have several different kinds of receptors. This image is just a simplified model, though. Mast cells actually have hundreds of receptors.

Mast cells sense what goes on in the body through these receptors. So when the receptors are triggered that can also trigger a mast cell response.

This picture shows a few things that can cause receptors to respond. Things like:

  • Pathogens –like viruses and bacteria
  • Antigens — Antigens are things we are truly allergic to. A true allergy is different from a sensitivity.
  • Mold and Candida
  • Medications
  • Hormones
  • There are even receptors that respond to the nervous system and neurotransmitters. Those are things like serotonin, the “feel good” neurotransmitter.

So as you can see, there are a lot of receptors playing a lot of different roles. And there’s a lot of communication between these receptors and mast cells.

For example, inside the mast cells there are things called granules
. The granules hold the mast cell chemicals, like histamine.

Degranulation is when those granules are triggered to release mast cell chemicals.

These chemicals are called mast cell mediators.

Dr. Lawrence Afrin is a well known mast cell researcher. We know there are definitely over 200 different mediators. According to Dr. Afrin’s latest counts, there may be over 1000 mediators! That’s over a thousand known chemicals that are released from mast cells.

When mast cell activation occurs, our bodies release these mast cell mediator chemicals. Many of these mediators are inflammatory. There are also some that are not inflammatory.

But either way, the release of these chemicals is called degranulation.

The mast cells can release just a few of these chemicals. This is called partial or piecemeal degranulation. OR they could release all of them at once. This is called total degranulation.

One of the most famous of these mediators is histamine. Histamine release is going to cause things like swelling, redness, and itching…these are just a few examples.

One of the challenges with Mast Cell Activation Syndrome is that these mediators from a few local mast cells can trigger the surrounding mast cells. And those mast cells can trigger more mast cells.

It’s like a forest fire that starts with a little spark and slowly burns out of control.

Mast Cell Triggers include:

  • toxic mold – this is the #1 trigger I see at Mast Cell 360
  • certain foods
  • chemicals (such as perfumes)
  • infections (like Lyme, EBV, etc)
  • hormone imbalances
  • lack of sleep
  • surgery
  • injuries
  • heavy metal toxicity
  • stress and trauma
  • certain genetics

Those are just a few possible triggers.

You can see there are a lot of potential triggers. And with so many mast cells in the body, the resulting symptoms can vary widely!

We’ll take a look at some signs and symptoms of Mast Cell Activation Syndrome next.

Signs and Symptoms – What to Know for People with Mast Cell Activation Syndrome and Histamine Intolerance

Signs & Symptoms Mast Cell 360 2

So, Mast Cell Activation Syndrome is a dysregulation of the mast cells. It happens when the mast cells become over-sensitive and overactive. Then your Mast Cells can over-release their inflammatory mediators.

Mast Cell Activation Syndrome is related but still different from Histamine Intolerance.

Histamine Intolerance is where you have trouble just with excess histamine.

Mast Cell Activation Syndrome is a problem with the Mast Cells and many types of these mast cell mediators, in addition to histamine.

Mast Cell Activation Syndrome is usually more severe than Histamine Intolerance. But many people with Mast Cell Activation Syndrome also have Histamine Intolerance.

Mast Cell Activation Syndrome is MUCH more common than it was once thought.

Mast Cell Activation Syndrome has been shown in population studies to be present in 9-17% of the general population. That’s at least 1 in 10 people. 

And over 50% of those with chronic illness will likely have Mast Cell issues.

It’s very common in families because of two things: genetic factors and environmental exposures (like chemicals and mold).

I always want you to understand that your mast cells are not the problem.

Your mast cells are absolutely essential.

In fact, there’s a rare disorder where people are born without mast cells. These people can’t survive in the world. If they do manage to survive, they have to live in a literal bubble. They can’t interact with the world.

So, we really do need our mast cells. We just want them to work FOR us – not against us.

But sometimes they do work against us. When that happens, certain symptoms can show up. 

These symptoms show up in all different body systems.

The list below shows some of the more common possible symptoms of Mast Cell Activation Syndrome. It doesn’t list everything. But it does show how Mast Cell Activation Syndrome can present in a lot of different ways!

  • Systemic Symptoms:
    • overall fatigue
    • inflammation
    • swelling
    • weight changes
    • sensitivities to foods, medications, environment, chemicals, EMFs, etc.
  • Musculoskeletal Symptoms:
    • osteoporosis
    • arthritis that moves around
    • muscle and/or bone pain
    • hyperflexible joints
  • Skin Symptoms:
    • itching
    • flushing
    • hives
    • rashes
    • hair loss
    • rosacea, psoriasis, eczema
  • Cardiovascular Symptoms:
    • fainting or feeling faint
    • chest pains
    • heart palpitations
    • dizziness
    • low blood pressure
  • Digestive Symptoms:
    • mouth burning
    • diarrhea and/or constipation
    • nausea
    • reflux or heartburn
    • food sensitivities
    • IBS
    • throat/tongue swelling
    • symptoms within 0 to 15 minutes of eating
  • Brain and Nervous System Symptoms:
    • brain fog
    • difficulty paying attention
    • headaches, migraines
    • depression, anxiety
    • tingling and numbness
    • tinnitus
  • Lung and Respiratory Symptoms:
    • congestion
    • coughing
    • shortness of breath
    • asthma
  • Reproductive System Symptoms:
    • endometriosis
    • painful periods
    • male and female infertility
    • hormone imbalances

After looking at these symptoms, are you wondering whether or not you or a loved one has Mast Cell Activation Syndrome?

Now, I bet you are wondering what you can do if you do think you have Mast Cell Activation Syndrome.

Let’s look at the root causes approach to Mast Cell Activation Syndrome next.

Mast Cell Root Causes – What to Know for People with Mast Cell Activation Syndrome and Histamine Intolerance

Root Cause Mast Cell 360

There are a number of root causes we look at in the Mast Cell 360 practice.

In this post, we’ll cover the top 3 Root Causes I see at Mast Cell 360 in more detail:

  • mold toxicity
  • nervous system dysregulation
  • food triggers.

You can get more information about these and other mast cell triggers by downloading your Free Report on the 7 Most Common Root Causes in Mast Cell Activation Syndrome here.

But today, we’ll look at these 3 I mentioned: mold toxins, nervous system dysregulation, and food triggers.

Mold Toxicity and Mast Cell Activation Syndrome

Mold Toxicity Mast Cell 101

First, let’s look at Mold Toxicity. It acts as a major trigger for the mast cells by:

  • Dysregulating and dampening the immune response to bacteria and viruses
  • Disrupting hormones
  • Causing the nervous system to go haywire
  • Clogging up detox pathways
  • Disrupting the gut

I’ve done a series of blog posts on mold. If you think mold might be an issue, take a look at these posts:

Mold toxicity is hands down the biggest root trigger I see at Mast Cell 360. It’s become an epidemic of sorts. At this point, over 95% of the people who come through our clinic have mold toxicity.

So, if you are dealing with Mast Cell Activation Syndrome, looking into mold toxicity is very important.

Next let’s look at nervous system dysregulation. It’s another common root cause I see.

Nervous System Dysregulation and Mast Cell Activation Syndrome

Nervous System Mast Cell 101

Nervous system dysregulation is where the fight/flight/freeze and rest/heal/repair parts of the nervous system gets out of balance. So, basically, you can get stuck in fight/flight/freeze. And this makes it very hard to rest, heal, and repair your body.

This kind of nervous system imbalance can cause all kinds of sensitivities. Like to light, sound, scents, and touch.

It can even cause issues with EMF, chemical, supplement, and medication sensitivities. On top of this, many people with nervous system dysregulation have trouble with anxiety, depression, sleep, and mood swings.

Mold is one of the worst triggers of both Nervous System Dysregulation and Mast Cell Activation Syndrome.

Nervous system dysregulation can also be worsened by structural issues, like neck vertebrae out of balance. Or fluid buildup on the brain. Or chiari malformation (where the brain drops into the hold in the skull for the spine).

A few other things that affect the nervous system are: stress, early traumas, Lyme and Lyme coinfections.

These are symptoms of nervous system dysregulation:

  • Difficulty falling asleep or staying asleep
  • Easily stressed
  • Easily startled
  • Feeling wired or tired
  • Anxiety, depression, or mood swings
  • Constipation or diarrhea
  • Sensitive to lights, sounds, touch, smells
  • Sensitive to chemicals
  • Sensitive to EMFs
  • Food reactions
  • Supplement or medication reactions 

There are mast cells at every nerve ending. And the mast cells and nervous system work very closely together. So you can actually help your Mast Cell Activation Syndrome by working on your nervous system!

This is also why I call mast cells that have become over-sensitive Haywire Mast Cells. It’s like the signaling gets mixed up.

You may just have mildly Haywire Mast Cells. Or you may have severely Haywire Mast Cells. The approach to fixing them is a little different depending on which category you’re in.

You can also learn more about what role the nervous system plays in Mast Cell Activation Syndrome by reading these blog posts:

And, if you have any sensitivities or are struggling with supplements, foods, or medications, then this course is a great next step for you:

And finally…let’s go over food triggers. 

Food Triggers and Mast Cell Activation Syndrome

Food Triggers Mast Cell 101

Inflammatory foods are a very common trigger in Mast Cell Activation Syndrome. They can set off inflammation in your digestive system. The main food trigger we think of with Mast Cell Activation Syndrome is high histamine foods.

However, lectins can also trigger mast cells. Knowing about lectins can be very important if you have any kind of autoimmunity or cancer history.

Some people can also be triggered by other food issues like Salicylates and FODMAPs. Especially in mold toxicity. But not everyone has trouble with these.

Definitely don’t limit your foods unnecessarily.

And never limit them too much. This can lead to many other problems.

If you are working on changing your foods, be sure to work with your healthcare practitioner and don’t ever get too limited.

If you aren’t sure where to start, in my practice most people try eating low histamine, low lectin for about 6 weeks to see if it makes any difference.

You can read about these additional food triggers in the following posts:

Now, if you are dealing with Mast Cell Activation Syndrome, the very good news is that you can really improve when you start addressing those root factors.

And that’s what we’ll look at next…

What to Do if You Have Mast Cell Activation Syndrome or Histamine Intolerance - Top 4 Mast Cell 360 Steps

The good news is that you don’t have to deal with this forever. You really can improve your health. To do that, you’ll want to identify and address your underlying causes.

I want to give you some resources and my top 4 starting steps when you’re dealing with Mast Cell Activation Syndrome.

First, though, I do want you to know there aren’t any quick and easy answers to overcoming Mast Cell Activation Syndrome.

Meds can reduce symptoms for the short term. And medications can be a very important part of recovery.

But I want you to know that anti-histamines and mast cell stabilizers don’t get rid of the underlying triggers. So, if you only use medications, Mast Cell Activation Syndrome tends to get worse over the long-term. This is why you want to address the root causes.

It takes work, time, and dedication to recover. But, I’m living proof that you can recover from Mast Cell Activation Syndrome.

I had Mold Toxicity, Lyme, Bartonella, Heavy Metals, Nervous System Dysregulation, and several other root triggers.

I was bedridden, couldn’t work, and barely able to hobble across the room with a cane. I had debilitating pain, fatigue, GI issues, and sensitivities to EVERYTHING.

I’ve recovered significantly.

So have the hundreds of clients I’ve worked with at Mast Cell 360.

And I believe you can too!

So, what are the most important 4 starting steps in recovering with Mast Cell Activation Syndrome? These are the exact 4 steps private clients in our Mast Cell 360 clinic start with:

Yes, this will take you time. But the rewards at the end can be well worth it.

50% of the work is supporting the rewiring of your body and mast cells. So, the nervous system is a great place to start. And you can do this on your own.

Our Mast Cell 360 Mast Cell Nervous System Reboot course will help you step through what to do and how to build your own Nervous System Reboot Map.

Are you ready to get started on the #1 step in the Mast Cell 360 process?

Be sure to check out the Mast Cell Nervous System Reboot here:

After that, you can take the Top 8 Mast Cell Supporting Supplements Master Class to learn about exactly which supplements I see best tolerated by sensitive people with Mast Cell Activation Syndrome.

I also teach you how to introduce those supplements in a way that can make you more successful in getting them onboarded.

Are you ready to get started on the #2 step in the Mast Cell 360 process?

Be sure to check out the Top 8 Mast Cell Supporting Supplements Master Class here:

Remember to take things at your own pace, and as always, be gentle with yourself.

It’s important you know that this blog post is for informational and educational purposes. It’s not meant to treat any health condition or to be prescriptive for anyone. Always be sure to work with your healthcare practitioner.

References for Mast Cell Basics – What to Know for People with Mast Cell Activation Syndrome and Histamine Intolerance

Afrin, Lawrence B. “A Concise, Practical Guide to Diagnostic Assessment for Mast Cell Activation Disease.” WJH World Journal of Hematology 3.1. 2014. 155-232.

Afrin, Lawrence, Dr. “Presentation, Diagnosis, and Management of Mast Cell Activation Syndrome.” Mast Cells: Phenotypic Features, Biological Functions and Role in Immunity. Nova Science, 2013. 155-232.

da Silva EZ, Jamur MC, Oliver C. Mast cell function: a new vision of an old cell. (2014). The Journal of Histochemistry and Cytochemistry: Official Journal of the Histochemistry Society, 62(10), 698-738. DOI: 10.1369/0022155414545334.

Krystel-Whittemore, M., Dileepan, K. N., & Wood, J. G. (2016). Mast Cell: A Multi-Functional Master Cell. Frontiers in immunology, 6, 620. https://doi.org/10.3389/fimmu.2015.00620

Lewis, Charles A. Enteroimmunology. Psy Press. Carrabelle Florida. 2016. 116-147.

Metcalfe D. D. (2008). Mast cells and mastocytosis. Blood, 112(4), 946–956. https://doi.org/10.1182/blood-2007-11-078097

Moon, T. C., Befus, A. D., & Kulka, M. (2014). Mast cell mediators: their differential release and the secretory pathways involved. Frontiers in immunology, 5, 569. https://doi.org/10.3389/fimmu.2014.00569

Spoerl, D., Nigolian, H., Czarnetzki, C., & Harr, T. (2017). Reclassifying Anaphylaxis to Neuromuscular Blocking Agents Based on the Presumed Patho-Mechanism: IgE-Mediated, Pharmacological Adverse Reaction or “Innate Hypersensitivity”?. International journal of molecular sciences, 18(6), 1223. https://doi.org/10.3390/ijms18061223

Stone, K. D., Prussin, C., & Metcalfe, D. D. (2010). IgE, mast cells, basophils, and eosinophils. The Journal of allergy and clinical immunology, 125(2 Suppl 2), S73–S80. https://doi.org/10.1016/j.jaci.2009.11.017

Theoharides, Theoharis C. “Critical role of mast cells in inflammatory diseases and the effect of acute stress.”  Journal of Neuroimmunology. 2004. 1-12.

Theoharides TC, Angelidou A, Alysandratos KD, et al. “Mast cell activation and autism.” Biochimica et Biophysica Acta. 2012. 34-41

Wernersson, S., & Pejler, G. (2014). Mast cell secretory granules: armed for battle. Nature reviews. Immunology, 14(7), 478–494. https://doi.org/10.1038/nri3690

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