Mast Cell Activation Syndrome (MCAS)
Individualized evaluation and care for patients with mast cell activation syndrome and complex mast cell-related symptoms.
Mast Cell Activation Syndrome (MCAS) is a condition involving inappropriate release of chemical mediators from mast cells, which can cause recurring symptoms affecting multiple areas of the body.
At Functional Medicine Collaborative, we work with patients experiencing complex symptoms or previously diagnosed mast cell activation syndrome using an individualized approach based on their symptoms, health history, previous testing, and healthcare needs.
What Is Mast Cell Activation Syndrome?
Mast cells are immune cells that release substances such as histamine and other chemical mediators as part of the body's normal immune response.
In Mast Cell Activation Syndrome (MCAS), episodes of inappropriate mast cell activation and mediator release can cause symptoms involving multiple body systems. Symptoms may affect the skin, gastrointestinal tract, respiratory system, and cardiovascular system.
Because many symptoms associated with mast cell activation can also occur with other health conditions, evaluation for MCAS involves more than symptoms alone.
Common Symptoms of Mast Cell Activation
Mast cell activation can cause episodes of symptoms affecting more than one area of the body. Symptoms can vary from person to person and may include:
Flushing, itching, or hives
Swelling of the lips, tongue, eyelids, or other areas
Abdominal cramping
Diarrhea
Nausea or vomiting
Wheezing or shortness of breath
Rapid heart rate
Low blood pressure
Dizziness, fainting, or near-fainting
The pattern of symptoms is important. MCAS typically involves recurrent episodes affecting multiple body systems rather than one isolated or persistent symptom.
Some patients being evaluated for mast cell-related concerns also report symptoms such as fatigue, headaches, difficulty concentrating, or reactions associated with certain foods or environmental exposures. Because these symptoms are not specific to MCAS, they should be considered within the patient's broader health history and clinical evaluation.
How Is MCAS Evaluated?
Evaluation for Mast Cell Activation Syndrome begins with a detailed review of your symptoms, including which body systems are affected, whether symptoms occur in episodes, possible triggers, and your overall health history.
When MCAS is suspected, laboratory testing may be used to look for evidence of mast cell mediator release. Testing may include serum tryptase and, when appropriate, urine testing for mast cell mediators or their metabolites.
Because mediator levels can change during an episode, the timing of testing can be important. Results are interpreted alongside symptoms, medical history, and other clinical findings rather than used alone to diagnose MCAS.
Ruling Out Other Conditions
Because symptoms associated with mast cell activation can overlap with allergies, gastrointestinal conditions, cardiovascular conditions, medication reactions, and other health concerns, evaluation may also involve considering other possible explanations for your symptoms.
In some patients, additional testing or referral to an allergist, immunologist, or other specialist may be appropriate.
Our Approach to MCAS
Our practitioners work with patients who have been diagnosed with Mast Cell Activation Syndrome as well as patients experiencing symptoms that may warrant further evaluation for mast cell-related concerns.
Care begins with a detailed review of your symptoms, possible triggers, health history, medications, previous testing, and other health conditions that may be relevant. Because MCAS can affect patients differently, evaluation and treatment are individualized rather than based on a single protocol.
Identifying Patterns & Triggers
Your practitioner will work with you to understand when symptoms occur, which body systems are affected, and whether particular foods, medications, environmental exposures, temperature changes, stress, or other factors appear to trigger or worsen episodes.
Individualized Treatment
Treatment recommendations depend on your symptoms, medical history, test results when applicable, and other health conditions. Care may include strategies to reduce known triggers, nutrition and lifestyle recommendations, medications, supplements, and other therapies when appropriate.
Coordinated Care
MCAS and similar symptoms may sometimes require evaluation or treatment from an allergist, immunologist, gastroenterologist, or other specialist. Our practitioners can work alongside other members of your healthcare team when additional evaluation or specialty care is needed.
Common MCAS Triggers
Mast cell activation episodes may be associated with a variety of triggers, and individual sensitivities can differ considerably from person to person.
Potential triggers may include:
Certain foods or beverages
Medications
Heat, cold, or sudden temperature changes
Physical exertion
Stress
Infections
Insect stings
Environmental exposures, including fragrances or other irritants
Not everyone with MCAS reacts to the same triggers. Identifying patterns over time can help patients and practitioners develop individualized strategies for managing symptoms.
Food & Histamine Sensitivity
Some patients with mast cell-related symptoms report reactions to histamine-rich foods or other dietary triggers. Dietary changes may be considered when appropriate, but restrictive diets are not necessary for every patient and should be individualized to avoid unnecessary nutritional limitations.
Common Questions About MCAS
Is MCAS the same as a food allergy?
No. MCAS and food allergies are different conditions, although some symptoms may overlap. A food allergy involves an immune response to a specific food, while MCAS involves episodes of mast cell mediator release that may occur in response to various triggers. A person can also have both conditions.
Can MCAS cause digestive symptoms?
Yes. Mast cell activation can cause gastrointestinal symptoms such as abdominal cramping, diarrhea, nausea, and vomiting. However, these symptoms are common in many other digestive conditions and do not establish an MCAS diagnosis on their own.
Can you have MCAS with normal bloodwork?
Yes. Routine bloodwork may be normal in people being evaluated for MCAS. Mast cell mediator testing can also be affected by when samples are collected, particularly in relation to symptom episodes. A diagnosis requires consideration of the clinical pattern, objective laboratory findings, and response to appropriate treatment. Normal routine bloodwork alone does not rule out MCAS.
MCAS Care in Massachusetts & Rhode Island
Our practitioners work with patients experiencing mast cell-related symptoms and those who have been diagnosed with Mast Cell Activation Syndrome (MCAS). Care is individualized based on each patient's symptoms, health history, previous testing, and healthcare needs.
Appointments are available at our South Dennis, Hingham, and Johnston locations, with virtual visits available when appropriate.
Schedule a free 20-minute consultation to discuss your health concerns, learn more about our approach, and determine whether Functional Medicine Collaborative may be a good fit for your needs.