The Agony of MCAS

LYME SCI: The Agony of Mast Cell Activation Syndrome (MCAS)

Lonnie Marcum, March 2018

In the winter of 2016, my 17-year-old daughter was dying. She had severe allergic reactions every day, was in constant pain, and was losing weight at a rate that was not sustainable to life. She had reached the end of her rope, and I was completely out of ideas on where to turn for help.

Eighteen months earlier, after a long illness and finally completing treatment for Ehrlichia chaffeensis, Bartonella and Lyme disease, she had been doing great. Unfortunately, she soon caught the flu and then everything went south.

Over the next year, one setback after another landed her in the hospital every other month with atrial-fibrillation (irregular heartbeat) and/or near-anaphylaxis (acute allergic reactions). Each trip to the doctor took one more piece of hope away from us, since no one could pinpoint the cause of her rapid decline.

Over time, my daughter developed allergies to soaps, perfumes, juices, fruits, vegetables, and lunch meats. Eventually, she was down to only two foods that didn’t make her lips swell, mouth break out in blisters and throat tighten–sauteed chicken and brown rice noodles.

Not knowing what to do, I reached out in desperation to the “LymeParents” Yahoo group. Another mother recognized the symptoms I was describing as mast cell activation syndrome (MCAS) and connected me with Dr. Lawrence Afrin at University of Minnesota. Dr. Afrin consulted on my daughter’s case, then referred us to Dr. Mark Renneker, a mast cell specialist at the University of California, San Francisco.

Soon, she received a diagnosis of MCAS, and with it a path to healing.

Coincidentally, one month after my daughter’s diagnosis, I attended Dr. T.C. Theoharides’ lecture on mast cell activation at ILADS in Philadelphia. In his words:

Mast cells are the “universal alarm cell” that starts the inflammatory cascade. They can be triggered by infection, allergens, environmental factors like pollution, or even emotional stress. Once that happens, mast cells set into motion a series of inflammatory reactions, including the activation of immune cells and the release of tumor necrosis factor-alpha (TNF-a), a pro inflammatory protein or cytokine.

If you or a loved one are in a similar situation, here’s what you need to know.

The Diagnosis

MCAS is a clinical diagnosis based upon signs, symptoms and response to treatment. There are a number of tests available to confirm the diagnosis, but negative tests do not rule out MCAS.

(For a complete guide to the diagnosis of MCAS, click here:

Mast Cell Activation Diseases

Mast cells are a normal part of our immune system. They are located in every organ and connective tissue of the body. When mast cells detect stress, injury, toxins or infection, they release specific chemicals which trigger an immune response. Think of them as sentries or guards.

When mast cells perform properly, they are our friends. When mast cells are agitated or over-reactive, the immune system goes haywire and starts to attack the body, triggering auto-inflammatory processes or some types of autoimmune illnesses.

There are two major forms of mast cell activation diseases (MCAD)

  • Mastocytosis—the abnormal accumulation of mast cells in one or more organ systems (cardiovascular, central nervous, digestive, endocrine, genitourinary, lymphatic, muscular, peripheral nervous, respiratory) which is diagnosed by a bone marrow biopsy or a C-Kit genetic mutation.
  • Mast Cell Activation Syndromes—the inappropriate release of mast cell mediators including: histamine, interleukins, prostaglandins, cytokines, chemokines, and heparin.

As far back as 1999, researchers were able to demonstrate how Borrelia burgdorferi induces mast cell activation, contributing to greater illness in Lyme disease.

Somehow, I feel this fact has remained under-appreciated until just recently.

(To view my previous blog on symptoms of MCAS, click here:

PTSD of the Immune System

When I describe my daughter’s condition to non-medical folks, I say it’s like her immune system has post-traumatic stress disorder (PTSD). After going a year with multiple untreated infections, her immune system was very depleted, and the combination of antibiotics she needed to fight her infections added additional stress. As she completed antibiotic treatment for her infections, we added supplements to boost her immune system and promote healing. Or so we thought.

Unbeknownst to her doctors and me, one of her prescription medications (ketotifen) contained lactose, which she is intolerant to. In addition, she had developed an allergy to microcrystalline cellulose (MCC), one of the most common fillers in prescription medications, vitamins and supplements. Eliminating these allergens was a major turning point in her healing.

Our Five Steps to Healing

Step 1 Reduce or eliminate mast cell triggers (common triggers)
  • Infection (bacteria, fungi, parasite, virus)
  • Insect bites (spiders, ticks, fleas, mosquitos, bed bugs)
  • Stress (heat, cold, fatigue, emotional stimuli)
  • Foods (dairy, fermented or aged foods, wheat, shell fish, sugar, preservatives)
  • Drugs (alcohol, hormones, antibiotics, anesthetics, opioids, aspirin, NSAIDS, excipients)
  • Dyes (food coloring, radiographic dyes, pigments in makeup)
  • Environmental toxins (pollen, dust, mold, animal dander, heavy metals, pesticides)
  • Noxious odors (perfumes, smoke, exhaust fumes, smog)

Step 2 Assemble the “A TEAM” (sample)

  • Physician knowledgeable about Lyme and other tick-borne diseases (treat infections)
  • Physician knowledgeable about mast cell activation syndrome (lower histamine, stabilize mast cells)
  • Psychotherapist (emotional support)
  • Physical therapist (modalities for pain, lymph drainage, home care instructions)
  • Doctor of Osteopathy (functional medicine, supportive hands-on therapy)

Step 3 Find the right combination of medications/supplements

Many people with mast cell issues will improve by taking antihistamines. Antihistamines are medications that block or inhibit the histamine receptors on mast cells and other cells found throughout the body.

Histamine is a unique chemical produced primarily by mast cells that causes inflammatory reactions and the itching feeling most of us are familiar with. Histamine also signals the immune system, regulates the digestive system, and acts as a neurotransmitter in the brain, spinal cord and uterus.

There are at least five different types of cells that respond to histamine (H1-H5 receptors) found throughout the body, although H1 and H2 appear to be the most common.

Antihistamines are classified by the type of receptor that they inhibit as listed below:

  • H1 blockers—act throughout the body (Allegra, Benadryl, Clarinex, Claritin, Silenor, Vistaril, Xyzal, Zyrtec, etc.) Note: Those that cause drowsiness cross into the brain.
  • H2 blockers—act mostly in the stomach (Pepcid, Prilosec, Tagamet, Zantac, etc.)
  • H3 blockers—act in the brain (Mostly experimental: Ciproxifan, Pitolisant)

Leukotrine inhibitors —act primarily in the airways (Accolate, Singular, Zyflo)

Mast-cell stabilizers—strengthen or stabilize the mast cell to reduce the release of histamine and other inflammatory chemicals (Cromolyn, Ketotifen, Hydroxyurea)

Tricyclic antidepressants—antidepressant that also sedate H1 receptors in the brain (Amitriptyline, Doxepin, Nortriptyline etc.)

Tyrosine kinase inhibitor—inhibits certain types of proteins that control a wide range of functions including cell growth (Imatinib)

Natural antihistamines and mast-cell stabilizers—natural supplements that act to block or clear histamine and stabilize mast cells (alpha lipoic acid, ascorbic acid, B6, diamine oxidase enzymes (DAO), luteolin, N-acetylcysteine (NAC), Omega-3’s, riboflavin, SAMe, quercetin, etc.)

Step 4 Customize Nutrition

Patients with certain genetic defects are more prone to MCAD. Looking into your genetics can help determine your predisposition to MCAD and/or histamine intolerance and help you design a customized nutrition plan.

Genetic defects related to MCAS:
  • KIT-D816V—KIT is a master regulator protein found on and in mast cells. A KIT mutation typically results in the mast cell being constantly activated. About 90% of patients with mastocytosis have a KIT-D816V mutation (there is a PCR test for this mutation).
  • MTHFR—The body makes several enzymes called MTHFR that are critical for the production of folate and many cellular functions. Patients with MTHFR defects may have an inability to clear histamine leading to MCAS and histamine intolerance.
  • HNMT—In the central nervous system, histamine is broken down by histamine methyltransferase (HNMT). Patients with a lot of HNMT defects will have trouble clearing histamine from the brain and nerves. Moodiness, sleep disturbance and frequent rashes or hives can be a sign of this.
  • ABPI—In the digestive tract, histamine is broken down by diamine oxidase enzymes (DAO). Defects in ABPI lead to lower levels of DAO and higher levels of histamine.
  • HLA—Variations in the HLA gene can increase the chances of gluten intolerance.
    VDR—VDR defects may lead to lower levels of Vitamin D, which is critical to immune health.
  • MAT—MAT gene is involved in the conversion of the amino acid methionine into SAMe. SAMe has 100s of critical functions throughout the body. If vitamin B12 makes you feel sick, you may have a lot of MAT defects. Your doctor can order blood work to check methionine and SAMe levels.


Genova Diagnostics, Tree of Life, Nutrahacker and Genetic Genie are the tools we used for my daughter. We also ran a complete vitamin and mineral panel to pinpoint nutrient deficiencies. Then, we designed a custom nutrition plan that was specific to her needs—I’ll describe it in detail in my next post.

Basic diet: Clean, fresh (nothing cured, processed or fermented), organic, gluten-free, dairy-free, dye-free, sugar-free, low-histamine, low-citrus, low-oxalate, low-nightshade.

Step 5 Stick to a Routine

Maintain the same sleep schedule
Maintain the same eating schedule
Maintain the same basic level of activity from day to day

Putting it all together

These steps may seem daunting. But when you are in a crisis like my daughter was, you are willing to go to extremes to get your life back. In my next post, I will share more details about what precisely we did.

Note: I am not a doctor. The information here represents my personal opinions and experiences. It is for informational purposes only—it is not intended to treat, diagnose, cure or prevent any disease.

LymeSci is written by Lonnie Marcum, a Licensed Physical Therapist and mother of a daughter with Lyme. Follow her on Twitter: @LonnieRhea Email her at: .


Mast cell activation disease: a concise practical guide for diagnostic workup and therapeutic options.

Full List of Publications and Presentations by Lawrence B. Afrin, M.D.

Borrelia burgdorferi Spirochetes Induce Mast Cell Activation and Cytokine Release

Recent Publications and Presentations by Theoharis C. Theoharides, Ph.D., M.D.


Great, great information here.  Many Lyme/MSIDS patients will improve dramatically when they consider MCAS and take active steps like the ones mentioned here.

Another option not mentioned is LDA/LDI.  My daughter’s Mast Cell issues are nearly resolved after this treatment that helps the immune system recognize “friend from foe.”  Go here for more on LDA/LDI:

For more: