Mast Cell Activation Syndrome (MCAS) and Lyme Disease

Mast Cell Activation Syndrome (MCAS) and Lyme Disease

What is Mast Cell Activation Syndrome (MCAS)?

Mast cell activation syndrome (MCAS), also commonly referred to as mast cell activation disorder (MCAD), is an immunological condition in which mast cells inappropriately and excessively release chemical mediators, resulting in a range of chronic symptoms, sometimes including anaphylaxis or near-anaphylaxis attacks. Primary symptoms include cardiovascular, dermatological, gastrointestinal, neurological and respiratory problems.In other words,  [source]

In other words, Mast cells are cells that generate an allergic reaction. Allergens binding to these cells cause the release of histamine, which causes immediate, and sometimes very intense, hypersensitivity reactions. Amy Yasko describes it this way, “Mast cells are like water balloons filled with histamine. When your body reacts to an allergen, it is like sticking a pin in the water balloon, allowing histamine to burst out.”

Mast cells can be found throughout the body. There is an abundance of mast cells beneath the epithelial surface of the skin and mucosal layers of the genitourinary, gastrointestinal, and respiratory tracts. Mast cells release a variety of mediators in response to external stimuli. In addition to mediators such as histamine, leukotrienes, and prostaglandins, they also secrete a variety of cytokines.

MCAS is a condition that affects multiple systems, generally in an inflammatory manner. Symptoms of MCAS are caused by excessive chemical mediators inappropriately released by mast cells. Mediators include leukotrienes and histamines. The condition can be different in different individuals and may be mild until exacerbated by stressful life events, or symptoms may develop and slowly trend worse with time. This makes it hard to diagnose.

MCAS is commonly found in patients with Lyme Disease,  Ehlers–Danlos syndrome (EDS) and postural orthostatic tachycardia syndrome (POTS).

Symptoms of MCAS

Symptoms will commonly take place after certain “triggers.” A trigger may be a food you eat, a drink you drink or an emotional or stressful event.


  • flushing
  • easy bruising
  • either a reddish or a pale complexion
  • itchiness
  • Cardiovascular
  • lightheadedness, dizziness, presyncope, syncope
  • Gastrointestinal
  • diarrhea, cramping, intestinal discomfort
  • nausea, vomiting
  • Swallowing, throat tightness
  • Psychological & Neurological
  • brain fog, short term memory dysfunction, difficulty with recalling words
  • headaches, migraines
  • Respiratory
  • congestion, coughing, wheezing
  • Vision/Eyes
  • ocular discomfort, conjunctivitis
  • Constitutional
  • general fatigue and malaise
  • food, drug, and chemical intolerances (especially fragrances)
  • sense of being cold all the time
  • Musculoskeletal
  • osteoporosis and osteopenia (including young patients)
  • Anaphylaxis: difficulty breathing, itchy hives, flushing or pale skin, feeling of warmth, weak and rapid pulse, nausea, vomiting, diarrhea, dizziness and fainting.

Common triggers include:

  • certain foods and drinks (especially alcohol, and high-histamine content foods)
    (See List Here)
  • temperature extremes
  • smells including perfumes, chemicals or smoke
  • emotional stress
  • hormonal changes, particularly during adolescence, pregnancy and women’s menstrual cycles
  • physical exertion or exercise
  • Fillers, binders and dyes in many medications are often the culprit in causing reactions, not necessarily the active agent, so patient’s sometimes have to use alternative formulations and compounding pharmacies.


Where to get Treated?

if you are physician or Naturopath that treats Mast Cell Activation Disorder please contact us here if you’d like to be listed on this post.

Common pharmacological and herbal treatments include:

Natural Treatments

Lifestyle changes:

  • Lowering stress
  • A low histamine diet

Here is a list of foods to avoid if you are trying to do a low histamine diet

Histamine-Rich Foods:

  • Avocados
  • Aged cheese
  • Citrus fruits
  • Cured meats: bacon, salami, pepperoni, luncheon meats and hot dogs
  • Dried fruit: apricots, prunes, dates, figs, raisins
  • Eggplant
  • Fermented alcoholic beverages: wine, champagne and beer
  • Fermented foods:  sauerkraut, vinegar, soy sauce, kefir, yogurt, kombucha
  • Fish: mackerel, mahi-mahi, tuna, anchovies, sardines and anything smoked
  • Nuts: walnuts, cashews, and peanuts
  • Soured foods: sour cream, sour milk, buttermilk, soured bread
  • Spinach
  • Tomatoes
  • Vinegar-containing foods: pickles, mayonnaise, olives, dressings

Histamine-Releasing Foods:

  • Alcohol
  • Bananas
  • Chocolate
  • Cow’s Milk
  • Nuts
  • Papaya
  • Pineapple
  • Shellfish
  • Strawberries
  • Tomatoes
  • Wheat Germ
  • Many artificial preservatives and dyes

DAO-Blocking Foods:

  • Alcohol
  • Energy drinks
  • Black tea
  • Mate tea
  • Green tea


Also Read: How To Naturally Boost Production Of The Histamine Degrading DAO Enzyme

MCAS is a  new diagnosis, being unnamed until 2007,


Mast Cell as Related to Lyme Disease

You may also be interested in learning about Mastocytosis.

Mast Cell Activation Syndrome Books

Learn More About

Histamine Intolerance

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