10/20/2025
Mast cells play a crucial role in the immune system. They’re found throughout the body, especially in tissues that interact with the outside world, such as the skin, lungs and gastrointestinal tract.
When activated by a trigger, mast cells release 200+ mediators – including histamine, prostaglandins and leukotrienes – that can affect many body systems. In mast cell diseases, these cells don’t behave normally, leading to amplified or unpredictable reactions.
Our first step guide provides reliable, accessible information to support patients, families and communities living with a mast cell disease. Visit mastocytosis-mcas.org to download.
mastocytosis-mcas.org/factsheets