What is Mast Cell Activation Syndrome

What is Mast Cell Activation Syndrome?

Mast Cell Activation Syndrome (MCAS) is a disorder characterized by the abnormal activation of mast cells, which are a type of immune cell that play a role in the body’s inflammatory response. Our bodies have an incredible immune system which consists of the thymus gland, lymphatic system (including the lymph, lymphatic vessels and lymphatic nodes), spleen, white blood cells, (including neutrophils, eosinophils, basophils, monocytes and lymphocytes such as T cells, B cells and natural killer cells), special tissue cells (including macrophages and mast cells) and special chemical factors (including interferon, interleukins, etc.). All of these parts work together to protect our body against infection and disease.

Ideally, we want to have a balanced immune system and not one that is overactive or underactive. If the immune system is too strong, it will result in conditions such as asthma, eczema, allergic rhinitis (allergies) as well as autoimmune diseases such as type 1 diabetes, rheumatoid arthritis, and lupus. If it is not active enough, conditions can range from the debilitating genetic “bubble boy disease” (severe combined immunodeficiency) to more mild conditions such as food or pet allergies, or catching  colds, flu, and other illnesses more often. Having a weak immune system can lead to a chronic cycle of getting sick, the immune system becoming weaker, and then further illness developing- a proinflammatory loop. 

Mast cells are a type of basophil (white blood cell made by bone marrow) that is in our blood vessels and releases histamine and other chemicals during an allergic reaction. Allergies are incredibly common, but their causes and manifestations are deceptively complex. At its root, an allergic reaction happens when the body interprets a stimulus as a threat to our health, and reacts in a way that provides a warning. Allergies are the result of our immune system releasing the antibody immunoglobulin E (or IgE), which will attach itself to mast cells that produce allergic reactions.

Once a mast cell has been activated, it breaks open and releases over 200 chemical messengers called mast cell mediators that are pre-stored or synthesized. Mast cell mediators include agents such as histamine, tryptase, heparin, leukotrienes and prostaglandins. There are many different results from this reaction, called degranulation, including hives, eczema, allergic rhinitis, asthma, GI issues and headaches. This is a result of most mast cells being found in the skin and mucous membranes of the respiratory and gastrointestinal tract.  In a healthy immune system, mast cells are helpful sentinels whose role is to warn and protect us from harmful agents. If they start to function abnormally, it can lead to more severe illness.

Mast Cell Activation Syndrome (MCAS) is considered a Mast Cell Activation Disorder (MCAD), a spectrum of immune conditions that occurs when there is a dysregulation of mast cells overproducing mediators. There are three main types of MCAS:

  1. Primary MCAS: occurs due to a genetic condition and results in hereditary alpha tryptasemia where too many mast cells are produced
  2. Secondary MCAS: occurs due to a known allergic reaction to things such as insect bites, medications, infections, or foods
  3. Idiopathic MCAS: occurs when no known trigger is present.

The excess chemical agents found in mast cell mediators cause severe allergy symptoms which can affect multiple body systems including the skin (hives, itching, sweating, swelling, rash and skin flushing), gastrointestinal tract (irritable bowel and diarrhea), respiratory (trouble breathing, wheezing, and coughing), eyes (itching and watering), nose (itching and running) mouth and throat (itching and swelling), bones and joints (flexibility and pain), mental symptoms (anxiety and depression), neurologic systems (dizziness and chronic fatigue) and heart (rapid pulse, low blood pressure, lightheadedness, and fainting).

MCAS can be a challenging condition to diagnose, as it shares symptoms with many other conditions and can present differently in different people. The best way to diagnose MCAS is by using four criteria: symptoms, treatment response, differential diagnosis, and biomarker tests. There is no known cure for MCAS, and most medical professionals suggest treatments that block the symptoms and not cure the inappropriate underlying response that occurs at a cellular level.

A functional medicine approach to treating MCAS may include dietary changes such as a low histamine/anti-inflammatory protocol, low-FODMAP protocol, or an elimination diet to find any food triggers. It may also include nutraceuticals such as Quercetin and glutathione, mind-body therapies like mediation and yoga which can downregulate the inflammatory cascade, immune healing IV treatment with vitamins, minerals, and ozone and supplements such as echinacea and red clove. All of these work to prevent and address the root cause of MCAS instead of just treating symptoms. At Meeting Point Health, we seek to rebalance the body using a natural and multi-system approach.

To benefit from a comprehensive, functional approach to treating Mast Cell Activation, call Meeting Point Health today at 215.298.9928 (Option 1).  You can also schedule a consultation by completing our online contact form at


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Medically reviewed by Dr. Stephen Matta, DO, MBA CAQSM and Mary Anne Matta, MS, MA, LAC

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