Association between Ehlers-Danlos syndrome and mast cell activation syndrome: Is there scientific evidence?

Ehlers-Danlos Syndromes (EDS) are hereditary connective tissue disorders that affect multiple systems. Mast Cell Activation Syndrome (MCAS) is a clinical condition characterized by chronic and aberrant activation of mast cells. This activation leads to the release of chemical mediators that cause a wide variety of symptoms across multiple organ systems. Both conditions share phenotypic similarities, particularly in symptoms associated with dysautonomia and immune-mediated manifestations. Various studies have linked both disorders at the pathophysiological and clinical levels. For example, pathophysiologically, the close and bidirectional interaction between fibroblasts and mast cells in the extracellular matrix has been highlighted; clinically, there is a high prevalence of MCAS-related symptoms in patients with EDS, especially the hypermobile type. In recent years, emerging evidence also points to a potential molecular association. The objective of this review is to evaluate the scientific evidence that exists between these two syndromes, at the pathophysiological, molecular and clinical levels.