Mastocytosis is a rare condition in which your body makes too many mast cells. There are 2 main types, cutaneous mastocytosis (mainly affects children) where mast cells gather in the skin and systemic mastocytosis (mainly affects adults) where mast cells gather in body tissues. There are 3 main subtypes of systemic mastocytosis. People with mastocytosis are an increased risk of anaphylaxis.
