Simply Stephanie

MCAS stands for Mast Cell Activation Syndrome. It is immunologic and not autoimmune. Reactions occur when mast cells (immune cells that live in tissues throughout the body) react to triggers and release chemical mediators. A reaction can look like a number of things: getting hives, facial flushing, fainting, dizziness, trouble breathing, throat tightening, abdominal cramping, or going into anaphylaxis.

Examples of triggers include foods and drinks, medications, environmental factors (fragrances, extreme temperatures, pollen, mold), exercise, stress, and viral or bacterial infections. MCAS exists on a spectrum, and people with this illness will not react to all of the same triggers and to the same degree.

To learn more about MCAS, you can visit the following sites:

American Academy of Allergy, Asthma, and Immunology

Cleveland Clinic

National Institutes of Health

The Mast Cell Disease Society