Mast Cell Activation Syndrome

Mast Cell Activation Syndrome (MCAS) is a condition where mast cells—immune cells involved in allergic responses—become overly active and release too many chemicals, such as histamine, into the body. This can cause symptoms like hives, swelling, stomach issues, difficulty breathing, and fatigue, often suddenly and unpredictably. MCAS is different from allergies because it’s caused by abnormal mast cell activity rather than an external allergen. It may be linked to genetic factors or other health conditions, and managing it typically involves medications to control symptoms and avoid triggers.