Management of Mast Cell Activation Syndrome (MCAS) Presented by David Saperstein, M.D. (MCAS) Mast cell activation syndrome is a condition where the allergic system goes haywire. This occurs in many patients with EDS, POTS, or Dysautonomias. Individuals with MCAS are prone to unpredictable rashes, hives, or skin sensitivities. ⁣ MCAS can be hard to diagnose. There are blood and urine tests, but these are frequently normal. Through the use of antihistamines, mast cell stabilizers, and other medic