4 facts you should know about MCAS

Some days, I feel like a walking public service announcement for mast cell disease. I want to save people from the suffering I have endured! I truly believe that if I had known about mast cell disease earlier, I could have avoided a lot of damage to my body. The problem is MCAS is generally unknown or at best misunderstood by doctors. Here are four basic facts that I wish more people knew about MCAS.

You don’t have to look like a tomato to have MCAS

My mast cells have wreaked havoc on my body my whole life, but I didn’t start flushing or getting hives until I was 29 years old. (And then they told me it was anxiety. Jerks.) For me, flushing and hives were the final sirens indicating my mast cell disease was out of control. A few months later, I started to have life-threatening, anaphylactic reactions. MCAS affects every part of the body and symptoms can include IBS, bone pain, tachycardia, migraines, and fatigue. Also, hives and flushing do not occur in 20% of anaphylaxis cases!

EDS and POTS are linked to MCAS

Do have EDS or POTS? Get tested for MCAS! There’s a good chance some of your symptoms are caused by misbehaving mast cells. I used to have to call in sick to work because I was too dizzy to stand up, let alone drive. On top of that, I was plagued with seemingly random injuries to my joints and tendons. MCAS treatment resolved my POTS symptoms and decreased my EDS related injuries. Wohoo!

Tryptase is usually normal in MCAS patients

When someone tells me their MCAS test was negative, I ask them, “Did you pee in the jug?” A tryptase blood test is just one of several MCAS tests, and the result is usually normal for MCAS patients. Mine was.

The 24-hour urine test is a MCAS rite of passage. It requires skill, because you have to keep your pee cold AT ALL TIMES*. This entails racing your urine to the refrigerator each time you pee and packing it in a cooler to bring to the lab. Mast cells release dozens of chemicals (not just tryptase or histamine) and the 24-urine test measures several of them. Unfortunately, even a minute of heat can destroy the chemicals, so many people have to repeat the test.

*There may be a 24 hour urine test that does not require refrigeration because it includes a preservative. Tests are evolving!

Pink pills can cause a MCAS reaction

Although the bright pink Benadryl tablets are fun images for blog post, don’t eat them! MCAS patients react to many inactive ingredients in medications, especially dye. Always check to make sure your medication is dye free. Even if the pill looks white, check for dye before purchasing!

7 thoughts on “4 facts you should know about MCAS

  1. I have to say that while I’m a newbie as far as an actual MCAD diagnosis goes, I’ve probably had MCAD forever and I can attest to everything you’re saying. I also didn’t start having facial flushing until my late 20s and didn’t start having anaphylaxis until only a few years ago. My tryptase is normal but I tested positive on my 24-hour urine the first time around. I was running around like a crazy woman trying to keep my urine cold too – so bad, in fact, that I accidentally dropped an entire cup of urine all over the floor – not my finest moment lol

  2. I have MCAS too got it after an allergic reaction to a flu shot. Had some allergies to meds before that but no where as bad. Could still eat everything , now forget it. I have all those symptoms too. Flushing but hardly any rashes.

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