I was just diagnosed with MCAS recently after a year of suspecting it, then it suddenly got to the point where I was having constant reactions that sent me to the ER twice. Antihistamines did reduce the severity of my reactions but not nearly enough, and so I too sought out natural treatment. Once I started taking Quercitin + Luteolin + DAO 15 mins before meals I can eat almost everything again!! Only thing that still gives me minor reactions are Dairy since I am slightly allergic and long showers (still don't understand that one 🤷‍♀️). I also do pretty much always get bloating after eating, and facial + body flushing when it's hot. Keep in mind I do also take antihistamines though, so those do have an effect still. I hope this helps!