MCAS Symptoms by Organ System
Eyes – Red eyes, irritated eyes, dry eyes, burning eyes, difficulty focusing vision, and conjunctivitis (pink eye).
Nose – Nasal stuffiness, sinusitis, postnasal drip, hoarseness, laryngitis, nose bleeds (epistaxis), and intranasal sores.
Ears – Ringing in ears (tinnitus) and Eustachian tube dysfunction (blocked, popping ears).
Throat – Vocal cord dysfunction, throat swelling, sores on tongue/mouth, itchy throat, burning mouth, and difficulty swallowing
Skin – Hives, angioedema (swelling of the skin), skin flushing, itching, skin rashes, dermatographism (when scratched skin causes a red welt), chronic itching, urticarial pigmentosa (legion/hive-like spots on the skin), flushing, bruising easily, reddish or pale complexion, cherry angiomata (skin growths), patchy red rashes, red face in the morning, cuts that won’t heal, fungal skin infections, and lichen planus.
Cardiovascular – Fainting, fainting upon standing, increased pulse rate (tachycardia), palpitations, spikes and drops in blood pressure, high pulse or temperature, high triglycerides, lightheadedness, dizzy, hot flashes, and postural orthostatic hypotension syndrome (POTS).
Respiratory – Wheezing, asthma, shortness of breath, difficulty breathing deep, air hunger, dry cough, chronic obstructive pulmonary disease (COPD), and chronic interstitial fibrosis.
GI Tract – Left upper abdominal pain, splenomegaly (enlarged spleen) epigastric tenderness, nausea, vomiting, diarrhea and/or constipation, abdominal cramping, bloating, non-cardiac chest pain, malabsorption, GERD/acid reflux, cyclic vomiting syndrome, colonic polyps, and gastric polyps.
Liver – High bilirubin, elevated liver enzymes, and high cholesterol.
Neurological – Numbness and tingling (especially in the hands and feet), headaches, migraines tics, tremors, pseudo-seizures, true seizures, waxing and waning brain fog, memory loss, poor concentration, difficulty finding words, and spells of cataplexy (suddenly becoming disconnected from and unresponsive or unreactive to the world around).
Musculoskeletal – Muscle pain, fibromyalgia, increased osteopenia, osteoporosis, weakness, and migratory arthritis (joint pain).
Coagulation – History of clots, deep vein thrombosis, increased bruising, heavy menstrual bleeding, bleeding nose, and cuts that won’t stop bleeding.
Blood disorders – Anemia, increased white blood cell count, platelets, decreased white blood cell counts, decreased neutrophils, decreased lymphocytes, decreased platelets, reductions in CD4 helper lymphocytes, reductions in CD8 positive suppressor lymphocytes, reductions or excesses of IgA, IgG, IgM, IgE, a known condition called MGUS, myelodysplastic syndrome (reduced red cells, white cells, platelets), and increased MCV (mean corpuscular volume).
Psychiatry – Anxiety, panic, depression, obsessive compulsive disorder (OCD), decreased attention span, attention deficit/hyperactivity disorder (ADHD), forgetfulness, and insomnia.
Genitourinary – Interstitial cystitis, recurrent bladder infections, sterile bladder infections, and frequent urination.
Hormones – Decreased libido, painful periods, heavy periods, infertility, and decreased sperm counts.
Dental – Deteriorating teeth.
Anaphylaxis – Difficulty breathing, itchy hives, flushing or pale skin, feeling warm after exposure, weak and rapid pulse, nausea, vomiting, diarrhea, dizziness and fainting.
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.
Here’s a relatively common situation:
A woman who struggles with chronic fatigue and malaise throughout her life gets pregnant and suddenly feels energetic and wonderful throughout her pregnancy. Studies suggest this could be because DAO levels are up to 500 times higher than normal during normal pregnancies.
Alternatively, a person who was previously quite healthy develops a bacterial infection, is prescribed a 10-day course of antibiotics and suddenly develops severe reactions to certain foods. When looked at closely, these foods are found to contain high histamine levels. The current fads of consuming bone broths and fermented foods such as sauerkraut and kombucha only help to exacerbate this condition.
Histamine can have a powerful effect on a person’s wellbeing, making it important to be aware of the symptoms that indicate MCAS.
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.
If MCAS is suspected at our office, I send patients home with Chapter 6 of the book Mast Cells – Phenotypic Features, Biological Functions and Role in Immunity by David Murray. This chapter was written by Dr. Afrin, entitled Presentation, Diagnosis, and Management of Mast Cell Activation Syndrome. It describes, system by system, most of the symptoms that can be attributed to this diagnosis. Patients then return the symptom check list, which we review together slowly in order to establish the clinical diagnosis. I then order the lab tests to prove its existence.
In Dr. Afrin’s own words, “The general presenting motif of MCAS is chronic multisystem polymorbidity, generally of an inflammatory theme and with assorted elements waxing and waning over time, sometimes in synchronization with one another but more often cycling with different periods and amplitudes. The range of mast cell mediators and their effects is so great that “unusual” presentations actually become de riguer.”
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.
In an effort to help you notice common triggers, below are 10 non-food and 10 food triggers that commonly provoke mediator release in those with MCAS.
10 Non-Food Triggers of Mast Cell Activation Syndrome
If you’re struggling or suspect you have MCAS, it’s in your best interest to reduce your exposure to these triggers, including:
- Extreme temperatures – either hot or cold
- Exposure to mold or Lyme disease and coinfections
- Emotional stress
- Insect bites
- Chemicals in personal products
- Medications that liberate histamine or block DAO
- Sodium benzoate –a common food preservative
- Airborne smells from chemicals or smoke
- Heavy metal toxicity – aluminum, mercury, lead, cadmium, bismuth and arsenic are known to be mast cell destabilizers
10 High Histamine Foods that Should be Avoided
Studies have shown that eliminating foods high in histamine and other triggers can significantly improve symptoms. Ten of the highest histamine foods include:
- Yeast and alcohol
- Dairy (especially fermented dairy like kefir)
- Fermented foods, especially sauerkraut, kombucha, miso
- Cured and smoked meats and fish
- Citrus foods – lemon, lime, orange
- Leftover and aged food – especially if left in the refrigerator and not frozen immediately
- Berries – strawberries, blueberries, raspberries