Mast cells are a kind of white blood cell present in most body tissues, with the highest numbers found in the airways, skin and gastrointestinal tract. They belong to the innate immune system — the body’s first line of defense — and help keep pathogens such as viruses, bacteria and other foreign particles in check.
Inside mast cells, sac-like granules stand ready to release their contents when a trigger appears — whether physical, emotional or environmental stress. These granules hold a range of substances, or mediators, such as histamines and cytokines, which are involved in the inflammatory response.
Mast cell activation syndrome (MCAS) is a condition marked by an inappropriate, excessive release of these mediators, which can lead to itching, rashes, abdominal pain, nausea, vomiting, diarrhea or even neuropsychiatric symptoms such as anxiety and depression. Both the triggers and the clinical signs of MCAS vary widely and may involve different organ systems, so every patient presents differently.
Possible MCAS symptoms include: brain fog, headache, anxiety, nasal congestion, itchy throat, shortness of breath, bloating, diarrhea, nausea, vomiting, bone or muscle pain, flushing, itching, hives, rashes, fainting, unstable blood pressure, bladder irritability, frequent urination, neuropathic pain, lightheadedness, vertigo, sleeplessness, fatigue, reduced attention span, rapid heart rate — and the list continues.
Common MCAS triggers include: food, alcohol, odors, temperature extremes (hot or cold), stress (physical, emotional or environmental), fatigue, dyes, preservatives or fillers in medications, insect bites and stings, pollen, latex and infections.
Diagnosis relies on a patient’s history, clinical presentation, laboratory data and how they respond to interventions.
Treatment for MCAS may involve lifestyle changes, reducing inflammation, a low-histamine diet and addressing infections. Medication options may include leukotriene inhibitors or mast cell stabilizers. Before starting any new medication or supplement, it is important to see a provider for a proper evaluation.
References:
Afrin, L. B., Self, S., Menk, J., & Lazarchick, J. (2017). Characterization of Mast Cell Activation Syndrome. The American journal of the medical sciences, 353(3), 207–215. https://doi.org/10.1016/j.amjms.2016.12.013
American Academy of Allergy Asthma & Immunology. (n.d.) Mast Cell Activation Syndrome (MCAS). https://www.aaaai.org/conditions-and-treatments/related-conditions/mcas
Krystel-Whittemore, M., Dileepan, K., & Wood, J. (2016). Mast Cell: A Multi-Functional Master Cell. Frontiers in Immunology. https://doi.org/10.3389/fimmu.2015.00620
