Figure 2.

Illustration of disorders related to pathologic mast cell activation and association between allergy, anaphylaxis, mast cell activation syndrome (MCAS), and mastocytosis. While there is a significant overlap between the conditions, the size of the circle does not accurately represent the true percentage of overlapping. For example, the estimated overlap between anaphylaxis and mastocytosis is approximately 35%. However, there is currently a lack of systematic studies providing a precise estimation of the overlap between anaphylaxis and MCAS.