06/17/2026
For 16 years, I lived with POTS. Then MCAS changed everything
Living with POTS was already hard enough. I was dealing with tachycardia, dizziness, air hunger, fatigue, blood pooling, heat intolerance, and all the unpredictability that comes with autonomic dysfunction.
But when MCAS showed up, it felt like my body suddenly became reactive to everything.
Foods.
Sunlight.
Friction to my skin.
Medications.
Heat.
Sweating.
Scents.
Insect bites.
Some of these things I never used to think twice about suddenly became huge triggers.
What some people don’t know is that POTS and MCAS are frequently seen together. Studies have found that a significant percentage of people with POTS also have mast cell activation syndrome(MCAS), with some research reporting rates around 30-40%.
And honestly, I suspect the real number may be even higher.
Both conditions are still underdiagnosed, and there are so many people struggling with symptoms who haven’t been diagnosed yet or who have been told it’s anxiety, stress, or something else entirely.
The overlap isn’t surprising when you look at what mast cells do. When mast cells release chemicals like histamine and other inflammatory mediators, they can affect blood vessels, heart rate, blood pressure, and the nervous system. Those effects can make POTS symptoms worse.
And when your autonomic nervous system is already struggling to regulate things properly, mast cell flares can feel even more intense.
For me, having both conditions has been far more challenging than having POTS alone.
I suspect COVID may have been the trigger that pushed me into developing MCAS, but I’ll never know for sure. It’s also possible I would have eventually developed it anyway, considering I already had POTS, Small Fiber Neuropathy, and hEDS.
What I do know is that life before MCAS and life after MCAS feels very different.
If you have POTS and keep experiencing things like flushing, rashes, unexplained reactions, food sensitivities, itching, hives, GI issues, or symptoms that make you feel like your body is reacting to everything, it may be worth learning more about mast cell disorders.
Sometimes the missing piece of the puzzle isn’t ‘just POTS.’ It’s realizing there may be more than one thing going on.