Treating Mast Cell Activation Syndrome (MCAS)

Mast Cell Activation Syndrome (MCAS) is a group of disorders with different causes, presenting with episodic (sporadic) multi-system symptoms.

MCAS is usually the result of mast cell mediator release, which often isn’t caught by routine lab tests.

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Mast Cell Activation Syndrome and Histamine: When Your Immune System Runs Rampant

Most people with MCAS have chronic and recurrent inflammation, with or without allergic symptoms.
This occurs when an aspect of the innate immune system becomes overactive and releases a flood of inflammatory chemicals, which may affect every organ in the body. The symptoms of MCAS will wax and wane over time.

Another way to think of this is the symptoms will flare up and go into remission, affecting different organs and body parts, over and over again throughout a person’s life, without a common unifying theme or established diagnoses to account for the patient’s presentation of symptoms.

MCAS can present subtly but may become more serious as an individual ages. If you were to chart the symptoms of MCAS on a timeline, beginning at birth you can often identify symptoms that began at a very young age.

For some, MCAS becomes a highly probable diagnosis when they notice that they have had various symptoms of an inflammatory nature over the years.

These symptoms may include:

  • Allergies as a toddler
  • Various skin rashes that came and went
  • Disturbed gut function (possibly diagnosed as irritable bowel syndrome (IBS), gastroesophageal reflux disease (GERD) or small intestinal bacterial overgrowth (SIBO))
  • Unexplained anxiety
  • Headaches
  • Insomnia
  • Poor wound healing

Any of these symptoms could indicate MCAS.

What are Mast Cells, Mast Cell Mediators, and Histamine?

Mast cells are types of white blood cells that release up to 200 signalling chemicals, or mast cell mediators, into the body as part of an immune system stabilizing defense response against foreign invaders (parasites, fungi, bacteria, or viruses), allergens and environmental toxins.

We need mast cells to protect us from infection, heal wounds, create new blood cells, and develop immune tolerance. However, in conditions in which these cells are dysfunctional or overactive, they can cause serious issues.

Mast cells are found in most tissues throughout your body. In particular, they are found in tissues that are in close contact with the environment such as your skin, airways, and gastrointestinal tract. Mast cells are also found in your cardiovascular, nervous, and reproductive systems.

12 Tips for Living With Mast Cell Activation Syndrome

Mast cell mediators are the preformed granules secreted by mast cells in response to an outside stimulus, which can occur very quickly, in milliseconds. Mast cell mediators include histamine, proteases, leukotrienes, prostaglandins, chemokines, and cytokines. Their job is to signal and guide other cells, tissues, and organs to respond to the hostile invaders. These mast cell mediators provoke potent inflammatory responses that can include urticaria (AKA hives—skin rash and swelling), angioedema (swelling beneath the skin surface), bronchoconstriction (airway constriction), diarrhea, vomiting, hypotension (low blood pressure), cardiovascular collapse, and death, all within a matter of minutes.

Detailed Symptoms of Mast Cell Activation Syndrome

Patients who come into my office with MCAS usually have multi-system, multi-symptom inflammatory responses. These symptoms have often caused them to trudge from doctor to doctor, undergoing rounds of testing, causing them to feel extraordinarily confused as to what’s happening to their body. Because the symptoms of MCAS have so broad a reach and differ so considerably from person to person, I’d like to break them down by nonspecific, general clues, and organ system signs.

The Hoffman Centre specializes in MCAS diagnosis and treatments. Please contact us to discuss how Dr. Hoffman can help you. Our staff will ask some preliminary questions and discuss your options with you.

Illnesses Associated with MCAS

There are a number of illnesses and conditions that can exacerbate MCAS, including chronic inflammatory response syndrome (CIRS), poor methylation as determined by genetic MTHFR defects (leading to low SAMe, which degrades histamine intracellularly), deficiencies in histamine-N-methyltransferase enzyme (HNMT; degrades histamine in the liver) and deficiencies in the gut-based diamine oxidase (DAO) enzyme, which degrades histamine found in food. Histamine is one of the many inflammatory mediators released by individuals with MCAS. For those with healthy DAO levels, nearly all the histamine derived from food sources are broken down by their DAO enzymes.

But when there’s a lack of DAO, histamine can assist in creating intestinal permeability and upregulated inflammation. If a person suffers from small bowel intestinal overgrowth (SIBO) or has significant small intestinal issues (called dysbiosis), the lining of the small intestine may be disrupted. This leads to even lower levels of the DAO enzyme and hence, intestinal permeability.

Histamine Intolerance is a Subset of MCAS

Mast cell activation syndrome (also referred to as mast cell activation disorder (MCAD)) is sometimes confused with histamine intolerance. The major difference is that with MCAS, a person’s mast cells secrete many mediators of inflammation, such as leukotrienes and prostaglandins, not just histamine—although histamine is an important component. Histamine intolerance is considered a subset of MCAS where too much histamine is released from mast cells, too much histamine is taken in by consuming histamine-containing foods, histamine is not broken down in the gut because of DAO gut enzyme deficiency, or not broken down in the liver because of HNMT deficiency.

However, histamine is not all bad; it serves useful functions as a neurotransmitter, helps to produce stomach acid, and is an important immune mediator when not in excess.

Diagnosis of Mast Cell Activation Syndrome

A proper diagnosis of MCAS requires the presence of several symptoms from the above list. In addition, other disorders should be ruled out by a specialist in functional medicine.

MCAS is so difficult to diagnose because it may present in so many varied ways that traditional health care providers are not always trained to assess. There is a tremendous range of possible presentations, with local and remote effects which wax and wane over time.

Lab tests can be done to check for mast cell mediators. Tryptase is one of the most common mediators released by mast cells in those with mastocytosis (abnormal numbers of mast cells), but not for those with MCAS (abnormal release of proinflammatory mediators by mast cells, but not an increased number, as in the much rarer mastocytosis). Lab tests can also check for other mediators, such as histamine and prostaglandins; however, most doctors and many labs, particularly those in Canada, will not run the tests that are required to make the diagnosis.

Sometimes patients are able to identify triggers of their MCAS. These may be food or non-food triggers. Pay close attention to what you’ve eaten and have been exposed to when symptoms worsen.

After symptoms have been identified, other conditions have been ruled out, lab tests have been analyzed, and some treatment techniques have proven to relieve symptoms, an official diagnosis of MCAS is made.

Please contact us to discuss how Dr. Hoffman can help you. Our staff will ask some questions and discuss your options with you.

More Information About Mast Cell Activation Syndrome

How can we help?

The Hoffman Centre specializes in MCAS diagnosis and treatments. Please contact us to discuss how Dr. Hoffman can help you. Our staff will ask some preliminary questions and discuss your options with you.

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Dr. Bruce Hoffman