What is Mast Cell Activation Syndrome?

Mast Cell Activation Syndrome (MCAS) occurs when the mast cells are over-reactive and over-release inflammatory chemicals into the body.

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Role In the Body

Mast Cell Activation Syndrome is caused when the mast cells are over-responsive. Mast cells play very important roles in the body, though. The mast cells are types of white blood cells within the immune and neuroimmune systems. The mast cells regulate the immune system and are involved in allergies and anaphylactoid reactions. Mast cells are important in wound healing, immunity, and blood–brain barrier function.

What Is Degranulation?

There are hundreds of different chemicals that can be released from mast cells. These chemicals are called mediators. The mediators are held in small sacs in the cell called granules.

When mast cell activation occurs, the mast cells release these inflammatory molecules into the body. This process is called degranulation. The mast cells can release just a few mediators. This is called selective degranulation or piecemeal degranulation.

Or mast cells can release all their mediators in complete degranulation. This complete release can result in anaphylaxis or anaphylactoid reactions.

Location In the Body

Mast cells are found in almost all tissues in the body. There are high concentrations of mast cells in the skin, gut lining, lung lining, lining of the bladder, blood vessels, nerves, tendons, ligaments, bones, and even the brain.

They are found in the mouth, eyes, and ears as well. This is why Mast Cell Activation Syndrome (MCAS) can cause so many different types of symptoms.

Mast cells exist throughout our bodies!

Mast Cell Mediators

The most famous of the mast cell mediators is called is histamine. Histamine causes swelling, redness, and itching. You may have noticed this when you get a cut that becomes infected. Or when you have an allergy.

There are many other chemicals as well that are released by mast cells, though.

Some you may have heard of include cytokines, prostaglandins, leukotrienes, tryptase, and reactive oxygen species.

These are all involved in creating and managing inflammation in the body.

When Mast Cells Lead To Mast Cell Activation Syndrome (MCAS)

Mast cells act as guards in the body, protecting our bodies from invaders. When there is a perceived threat from a virus, bacteria, parasite, or even an allergen, the mast cells are activated to release chemicals to protect our bodies.  The mast cells release chemicals, such as histamine, attracting other key players of the immune defense system to areas of the body where they are needed.

Problems can occur, however, either when there are abnormally high levels of mast cells (this is called mastocytosis) or when there are normal levels of mast cells, but they are hyperresponsive (this is Mast Cell Activation Syndrome). Mastocytosis is fairly rare. Mast Cell Activation Syndrome, however, may be much more common than previously thought, according to Dr. Afrin and Dr. Theoharides. This site focuses on Mast Cell Activation Syndrome. (If you have mastocytosis, please reach out to a mastocytosis medical expert like Dr. Afrin or Dr. Theoharides.)

One of the challenges with Mast Cell Activation Syndrome (MCAS) is that many things can trigger further mast cell activation and degranulation. It is like a forest fire that starts with a little spark and slowly burns out of control. Triggers like certain foods, chemicals (such as perfumes), infections, hormone imbalances, temperature extremes, lack of sleep, alcohol, surgery, injuries, heavy metal toxicity, and even stress can cause more mast cell activation and degranulation. Genetic factors that increase inflammation can be a big underlying factor as well.

Managing Mast Cell Activation Syndrome means managing triggers and systemic inflammation as much as possible. This includes bypassing genetic issues causing inflammatory issues with supplements, choosing foods to decrease inflammation and support mast cell stabilization, making good lifestyle choices to decrease stress, and optimizing emotional wellness.  

What Causes Mast Cell Activation Syndrome?

Those with Mast Cell Activation Syndrome (MCAS) are like the canaries in the coal mine. We have immediate reactions to things like pesticides, perfumes, junk foods, pollution, and inflammatory triggers, that may take others years to react to. These things are hurting all of us, but when you have Mast Cell Activation Syndrome, it catches up to you quickly.

The cause of Mast Cell Activation Syndrome is an area up for much debate, however we have a number of ideas. There are genetic factors that contribute to MCAS, and we have just started scratching the surface here. I believe any genetic factors that contribute to increased inflammation could contribute to mast cell degranulation. By managing inflammation through food choices, lifestyle, supplements, appropriate levels of exercise, good sleep, and emotional wellness, we can decrease mast cell activation and may even be able to normalize our mast cells over time, dramatically improving our health!

Contributors to Mast Cell Activation Syndrome can include: Detox pathway issues, difficulty breaking down histamine, consuming excess histamine in diet, infections (like Lyme and Epstein Barre), toxic mold exposure, chemical sensitivities, vaccine reactions (for those who are susceptible), iron and copper oxidation, ammonia buildup, toxic exposures, and chronic stress.

What are Mast Cell Activation Syndrome (MCAS) Symptoms?

MCAS symptoms can occur in different systems in the body, and may include any number of the following:

General: overall fatigue and feeling bad, food, drug, environmental, and chemical sensitivities, chills, sweats, sense of being cold all the time, inflammation, swollen lymph nodes, swelling

Muscles/Skeleton: osteoporosis and osteopenia (even in young people), arthritis that moves around, general muscular and bone pain, hyperflexible joints, degenerative disk issues

Skin: flushing, hives, easy bruising, reddish or a pale complexion, itching, burning sensations, dermatographia (persistent redness or white marks after scratching skin), slow healing of skin, hair loss, rosacea, psoriasis, eczema

Heart: feeling faint or fainting, chest pains, fast heartbeat, heart palpitations, dizziness and lightheadedness when standing up, low blood pressure

Digestion: mouth burning, gum inflammation, diarrhea, constipation, cramping, abdominal pain, nausea, vomiting, reflux, trouble swallowing, throat tightness, malabsorption, bloating, elevation of liver enzymes, high cholesterol, food sensitivities and food allergies, irritable bowel syndrome, and obesity may occur due to fat metabolism and absorption issues

Brain and Nervous System: brain fog, short term memory issues, trouble recalling words, headaches, migraines, depression, loss of pleasure in life, nerve pains, trouble with attention, anxiety, insomnia, dizziness, tinnitus, numbness, sweating, temperature changes, tingling and numbness in arms and legs

Lungs and Respiratory: congestion, coughing, shortness of breath, wheezing, asthma, increased mucous production, post nasal drip, sinus congestion, frequent throat clearing, sinus and/or nasal swelling, nasal polyps

Eyes: eye pain, redness, trouble focusing, inflammation in the eyes, blurry, itchy, watery, irritated

Reproductive System: endometriosis, painful periods, male and female infertility, hormonal imbalances

Urinary Tract Symptoms: inflammation of tissues, burning, pain with urination, urinary tract infection type symptoms

Anaphylactiod Reactions (can be life threatening): difficulty breathing, itchy hives, flushing or pale skin, feeling of warmth, weak and rapid pulse, nausea, vomiting, diarrhea, dizziness and fainting.

Other conditions that may be related to MCAS: Fibromyalgia, Chronic Fatigue, Interstitial Cystitis, certain cancers, Crohn’s disease, diabetes, Ehrler’s Danlos Syndrome (EDS), Postural Orthostatic Tachycardia Syndrome (POTS), Autoimmunity, such as Rheumatoid Arthritis, Lupus, Hashimoto’s Thyroiditis, and Multiple Sclerosis, Autism Spectrum Disorders (due to the mast cell/brain connection)

People don’t have to have all of these symptoms at all. Usually at least 2 systems are affected, so for example digestion and skin symptoms or insomnia and chemical sensitives. Some people may only notice symptoms in just one system without being aware of issues in other systems.

Wondering if have Mast Cell Activation Syndrome?
Take the Mast Cell Activation Syndrome Symptoms Survey Here.

So What Can We Do About Mast Cell Activation Syndrome?

The good news is, there is a lot we can do to help manage our symptoms, support our bodies’ natural healing processes, and to feel better. I’m always very up front, and I want you to know this isn’t a quick fix and there are no guarantees. However, 95% of the clients I’ve worked with through this process so far have seen improvements, and many have gone on feel much, much better. While it does take work to get better, we have the possibilities and opportunities to heal, regain our lives, and live to our fullest potential.

For more information on MCAS and tips to support your healing, read this next: Mast Cell Activation Syndrome 101: The Beginner’s Guide to Healing.

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Mast Cell Aware

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.

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

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