[Severe Mast Cell Activation Syndrome in a 15-year-old patient with an hypermobile Ehlers-Danlos syndrome].

We report the history of a 15-year old patient with a hypermobile Ehlers-Danlos syndrome (hEDS) (his mother, his two brothers and his sister have the same phenotype as him). He suffers mainly from a severe mast cell activation syndrome (MCAS) with an overreaction of the skin to any kind of contact (water of the shower, clothes, bed sheets) but he has also fatigue, headaches, and rash. This impressive rash is exacerbated after the shower and he has the urge to rest («shower's sign»). We describe the MCAS and its easy, fast and very effective medication management, without any significant side effects as well as its frequent association with the hEDS. We finally introduce the original term of «MASED» to this MCAS, associated, linked or entangled to hEDS.