What is MCAS?

Mast Cell Activation Syndrome (MCAS) is a condition in which mast cells — the immune cells responsible for releasing chemical mediators such as histamine and heparin — become overactive. This overactivity leads to a flood of inflammatory chemicals entering the bloodstream, potentially affecting multiple organs throughout the body.

Symptoms of MCAS can vary widely, but may include:

• Recurring allergies and skin conditions from childhood
• Unexplained anxiety
• Digestive issues, including IBS, SIBO, and GERD
• Insomnia and disturbed sleep
• Frequent headaches
• Poor wound healing

Several factors can trigger mast cells to become overactive, including:

• Small intestinal bacterial overgrowth (SIBO)
• Imbalances in the gut microbiome
• H. pylori infection in the stomach
• Tick and insect-borne infections
• Mould and chemical exposures
• Underlying autoimmune conditions
• Genetic predispositions or gene variants
• Other conditions that mimic MCAS symptoms

Diagnosing MCAS can be challenging due to its systemic nature, affecting multiple organs and presenting with a wide range of symptoms. There is currently no single definitive test for MCAS. While blood tests measuring histamine and other mediators can provide helpful information, diagnosis is often a process of elimination combined with a thorough clinical assessment.

If you experience many of the symptoms listed above, MCAS could be a possible underlying factor. Accurate diagnosis and management require careful evaluation of triggers, underlying conditions, and your overall immune function.