Mast Cell Activation Syndrome (MCAS), Postural Orthostatic Tachycardia (PoTS), and Ehlers-Danlos Syndrome (EDS)

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Written By: Hannah Chapeskie 
Dietetic Intern, Acadia University


​Mast Cell Activation Syndrome (MCAS), Postural Orthostatic Tachycardia (PoTS), and Ehlers-Danlos Syndrome (EDS) are three conditions that commonly occur together and affect women more often than men. These rare conditions can go mis- or undiagnosed as their symptoms can overlap with other conditions and many physicians are unaware of their existence. Keep reading to learn about these conditions.
Have you been diagnosed with one of these conditions and are seeking dietary guidance? Book with one of our dietitians today!Mast Cell Activation Syndrome (MCAS)
Mast Cell Activation Syndrome (or MCAS) is a rare condition that involves repeated episodes of allergy symptoms or anaphylaxis, often without a known trigger. Mast cells are cells that are a part of our immune systems and are responsible for allergy symptoms. When a person encounters their allergy trigger(s), these cells release chemicals (called mediators) that cause inflammation and allergy symptoms. In MCAS, a person’s mast cells produce these chemicals in excess or in response to unharmful triggers such as foods, emotions, pain, fatigue, heat, smells, hormonal changes, and even the sun. A person with MCAS can have multiple triggers that change over time making it very difficult to identify exactly what is causing their symptoms.

MCAS Symptoms
The symptoms of MCAS can be different for every person. Symptoms can range from mild to anaphylaxis and can change over time. MCAS symptoms can affect many parts of the body including:

  • Skin: hives, flushing, itchiness, sweating
  • Eyes and Nose: itchy and watery eyes, itchy and runny nose
  • Mouth and Throat: itchiness, swelling of tongue or lips or throat
  • Respiratory: difficulty breathing, wheezing
  • Cardiovascular: low blood pressure, rapid heart rate
  • Gastrointestinal: cramping, diarrhea, nausea, stomach pain, bloating
  • Muscles and Joints: muscle and joint pain
  • Nervous System: headaches, dizziness, confusion, fatigue
  • Neurological: brain fog, tingling skin, anxiety

MCAS Cause
It is unknown what causes MCAS, but it is thought to be genetic. 74% of patients have at least one first degree relative who also suffers from this condition.


MCAS Diagnosis
Your doctor will review your medical history, complete a physical exam, and a urine and/or blood test. You may also be asked to keep a log of your reactions including potential triggers to help narrow down the cause or causes.In order to be diagnosed with MCAS, you must meet the following criteria:

  • Reactions are reoccurring
  • The symptoms of reactions affect two or more of your body systems
  • Blood or urine tests show elevated levels of mast cell chemicals (mediators) during a reaction
  • Trials of medications that block the function of mast cells result in symptom relief
  • Other conditions such as infections, irritable bowel syndrome, autoimmune disorders, adrenal insufficiency, and cardiovascular diseases have been ruled out


MCAS Treatment
There is currently no cure for MCAS, but symptoms can be managed with lifestyle changes and medication. If you are able to identify triggers, try your best to avoid them and seek guidance from a dietitian if it requires altering your diet. It is also recommended that people with MCAS avoid using NSAIDS like aspirin and ibuprofen as they can trigger a reaction. You may be prescribed medication such as antihistamines, mast cell stabilizers, anti-leukotrienes, or corticosteroids to help treat symptoms and supress reactions.Have you been diagnosed with MCAS and are seeking dietary guidance? Book with one of our dietitians today!


Postural Orthostatic Tachycardia Syndrome
Postural Orthostatic Tachycardia (or PoTS) is a rare condition that involves feeling dizzy or fainting when going from a seated, or reclined position to standing, and sometimes when standing for long periods of time. When a healthy person stands, their blood vessels constrict, and heart rate slightly increases to allow blood to continue to get to their heart and brain. In PoTS, the nervous system does not properly adjust to this change in body position resulting in an extreme increase in heart rate, a restriction of blood flow to the brain, and an increase in the chemical norepinephrine in the blood wh
ich is responsible for our fight or flight response. PoTS affects about 1% of the population and 90% of those diagnosed are female.

PoTS Symptoms
The symptoms of PoTS can be different for every person and can range from mild to debilitating. Symptoms tend to be worse in the morning and can persist for 2-5 months or lifelong. In PoTS, symptoms are triggered when one goes from laying or sitting to standing, and/or during periods of prolonged standing. Symptoms can include:

  • Light-headedness/dizziness
  • Racing heart
  • Shakiness
  • Chest pain
  • Difficulties sleeping
  • Headaches
  • Fatigue
  • Chronic pain
  • Gut symptoms – nausea, vomiting, diarrhea, constipation, bloat, abdominal pain
  • Symptoms while exercising (exercise intolerance)
  • Brain fog
  • “PoTS feet” – purple, swollen hands and feet

PoTS symptoms are typically relieved when one returns to a seated, or reclined position. Symptoms can also be aggravated by heat, eating refined carbs, changing position quickly, dehydration, menstrual periods, alcohol, and periods of prolonged bed rest.

PoTS Cause
The cause of PoTS is unknown, but it is thought to be genetic. Some abnormalities that may cause PoTS include impaired nerve function, prolonged bedrest that leads to loss of muscle tone and heart strength, as well as an elevated fight or flight response. Symptoms seem to begin after life events such as puberty, pregnancy, major surgeries, excessive blood loss, viral illnesses, and/or menstrual periods.


PoTS Diagnosis
Your doctor will review your medical history and complete a physical assessment. They will also do routine blood work and may use an ECG to rule out heart conditions. If your doctor suspects that you may have PoTS, you will likely undergo the Active Stand Test which is where your heart rate and blood pressure are measured when you are lying down, and then 2, 5, and 10 minutes after you stand up.
In order to be diagnosed with PoTS, you must meet the following criteria:

  • Experience PoTS symptoms mostly when upright over a period of at least 3 months
  • Have a sustained increase in heart rate over 30BPM (or 40BPM in teenagers) within 10 minutes of standing
  • Have no drop in blood pressuring on standing when experiencing PoTS symptoms

PoTS Treatment
There is no cure for PoTS, but diet and lifestyle changes, as well as medication can help manage symptoms. You may be prescribed a high sodium diet of 10g of salt/day, or sodium tablets if it is safe in your situation. You will also be encouraged to drink 2-3L of fluid/day and to avoid large meals of refined carbs as this can trigger symptoms.

Patients with PoTS often experience symptoms while exercising, leading them to avoid exercise which can make PoTS symptoms worse. Individuals with PoTS should progress to 30mins of exercise, every other day. Participating in exercises that do not require standing such as swimming, rowing, recumbent biking, and/or Pilates until symptoms improve can be beneficial.Wearing class 2 compression tights to help with symptoms and avoiding triggers such as heat and prolonged standing help with symptom management. Learning and practicing maneuvers to prevent fainting such as crossing the legs and clenching the fists and abdominal muscles can be helpful when it is not possible to avoid prolonged standing.

Medication is used as a last resort in PoTS as most patients can find relief in diet and lifestyle changes. Medication that increases blood pressure, increases blood volume, and/or slows heart rate can be prescribed if necessary.

Have you been prescribed a high sodium diet for PoTS symptoms? Our dietitians can help you with this dietary change!


Ehlers-Danlos Syndrome
Elhers-Danlos Syndrome (or EDS) is a group of disorders that affect the connective tissues in the body which includes bones, cartilage, ligaments, tendons, and skin. In EDS, the structure or production of collagen, the main protein that makes up our connective tissues, is abnormal due to defective genes. EDS affects 1/5,000 people and occurs more commonly in women. There are a total of 13 different types of EDS with the most common being Classic EDS and Hypermobile EDS.EDS Symptoms
In all classes of EDS, sufferers experience pain and fatigue. However, symptoms can vary between each type of EDS. In the two most common types, symptoms can include:
Hypermobile EDS

  • Loose joints
  • Easy bruising
  • Muscle pain
  • Muscle fatigue
  • Chronic degenerative joint disease
  • Premature osteoarthritis
  • Chronic pain
  • Heart valve problems

Classic EDS

  • Loose joints
  • Highly elastic, velvety skin
  • Fragile skin
  • Skin that bruises easily
  • Redundant skin folds on the eyes
  • Muscle pain
  • Muscle fatigue
  • Benign growths on pressure areas (elbows and knees)
  • Heart valve issues


EDS Cause
All classes of EDS are genetic meaning the condition is inherited.
EDS Diagnosis
Your doctor will review your medical and family history. During a physical exam, your doctor will assess for hypermobility in your joints and will note the texture of your skin, how easily it scars, and how much it stretches. If available, you can complete genetic testing using a blood sample to determine exactly which of your genes i
s abnormal, allowing your doctor to identify which type of EDS you have (genetic testing is not completed for Hypermobile EDS as we do not know which gene is affected in this condition).To be diagnosed with Hypermobile EDS, you must:

  • Have hyper joint mobility and two or more of the following:
    • A connective tissue disorder
    • A family history of EDS
    • Bone or muscle complications

To be diagnosed with Classic EDS, you must:

  • Haver hyper joint mobility
  • Have elastic skin that scars easily
  • Have a mutation in the genes COL5A1 and COL5A2 (determined through blood and genetic testing)


EDS Treatment
There is currently no cure for EDS. Those with EDS greatly benefit from receiving regular physical therapy to strengthen muscles and ligaments to prevent dislocations and pain. You may be advised to avoid contact sports and lifting weights and to try wearing assistive devices that eliminate pressure on the joints. When outside, individuals with EDS should always wear sunscreen as their skin can be very delicate and requires protection. In some cases, a patient may require surgery to repair damaged or dislocated joints and may be prescribed pain medication if experiencing regular, significant pain.
These three conditions, though rare, are becoming more common. They most often impact women and can occur together as a triad. If you suspect that you may have Mast Cell Activation Syndrome (MCAS), Postural Orthostatic Tachycardia (PoTS), Ehlers-Danlos Syndrome (EDS), or a combination of these conditions, book an appointment with your physician for guidance.Looking for general nutrition advice and guidance? The dietitians on our team are specialized in multiple areas to help you find the perfect fit!

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