Allergic to Living: Mast Cell Activation Disorder

What is Mast Cell Activation Disorder, or MCAD? What does it look like? How do you find out if you have it? How do you treat it?

I’ve mentioned MCAD (Mast Cell Activation Disorder, aka MCAS – or Mast Cell Activation Syndrome) before, and many of my readers are, unfortunately, already all too familiar with this condition. Y’all can run along, now, if you want, because I’d hate to bore you; this post is for the many readers who have written to ask me “What is this MCAD thing you keep mentioning?”

Here’s my unique way of explaining Mast Cell to people. I hope you’ll appreciate that I will attempt to be technically accurate and also funny. Which is hard. Really.

Before I start, I have to say that I am not a doctor and I do not play one on TV. This is my own interpretation of my personal medical condition, and though I always strive for accuracy and truth, I may well have some parts wrong or just not very thorough. Consult your doctor, and don’t take my word for it!

Everyone has Mast Cells. In all my reading I remember seeing the theory that mast cells are necessary for life, as they had yet to discover anyone who didn’t have them. So, cool! Right?

Right. Except for two groups of people: those who have too many  mast cells, and those who have the right number of mast cells…only theirs misbehave.

Too many mast cells is called Mastocytosis, and misbehaving mast cells is called MCAD (or MCAS).

My mast cells are in dire need of a spanking or a time out, because those little…things…misbehave all the time for me!

Well, if mine misbehave, what are mast cells supposed to do?

Simply put, mast cells are a part of the immune system that serve as a warning system and “first responder”. When normal people get a bee sting or some other form of injury, it is their mast cells that turn on their body’s “wee-oo, wee-oo” siren telling all the other systems that there is a problem, and mast cells tend to be proactive in flooding the body with histamine and other chemical goodies to help stabilize things.

Mast cells kind of rock at keeping us, you know, alive.

But when your mast cells misbehave, they wreak havoc.

Imagine if you were just walking down the street and out of nowhere, an ambulance pulls up, the paramedics jump out and grab you, strap you onto a gurney, start an IV, inject you with glucose, secure your neck in a stabilizing collar and shove an oxygen mask on your face.

Would you be shocked? Surprised?

Yeah, I bet you would.

Especially when it is revealed that the paramedics just got confused; you looked like the person they’d been called out to treat. Only, you weren’t that person.

That’s kind of what happens to people with MCAD. Our mast cells just get confused and react to weird stuff at weird times; notably things that are actually not  a problem for our bodies.

So, see, my “triggers” are actually just fine for my body. But my mast cells are all confused and act like they are a problem, which makes  them a “trigger” that is dangerous for my body.

Got it?

So what does MCAD look like?

Not to steal from the autism world, but, if you’ve met one person with MCAD, you’ve met one person with MCAD. The list of symptoms is robustly long, and no two people are going to react exactly the same. My very good friend (the one who helped guide me to a specialist) and I often joke about how our individual diets would kill the other one, and we both have MCAD, and our children both have FPIES. Go figure.

Even better, as I’ve mentioned, some MCAD people are “shockers” and others are “leakers”. Shockers tend to react quickly and life-threateningly to triggers (think anaphylaxis), whereas leakers (like me, so far) just degranulate slowly. As my doctor put it, “MCAD doesn’t affect life expectancy, it just makes your life very, very miserable.”

What is degranulation?

Well, it is a fancy word for “explode”. Here’s a nifty video (and pretty excellent article) of mast cells degranulating. Yep. My mast cells actually explode in my body and release whatever chemical they think my body needs to regulate healing.

Unfortunately, my body wasn’t sick, didn’t need healing, so the “cure” becomes the sickness.

I’ll give you a couple of real life examples to make it clearer. Remember my spinach reaction? Right. Worst pain in my life second only to childbirth. I ate spinach, which is high in histamine and salicylates, and my mast cells went all “Red alert! Red alert! We have an invader! Call out the troops! We must go to war!” giving me a headache that shot straight from the top of my head all the way to my toes, along with body aches, muscle pain, and an overwhelming desire to die…or at least go into a coma until the PAIN WENT AWAY.

Let’s not forget the chronic sinus infections I’ve had my whole adult life. The year I was married to my ex-husband, my sinus infections were so relentless the ENT finally gave up and said the only thing left she could think of was exploratory surgery  to discover the cause of my unending sinus infections. (Sinus infections which almost cost me my job, seeing as how sinus infection for a Flight Attendant equals grounded.) The day my ex walked out, my sinus infections stopped.

For six months, at least.

Clearly, stress is a major trigger for me. Along with heat, cold, anxiety, hormones, many foods, perfumes, chemicals, and who knows what else. (Full body hives? Rashes that stump the pathologist? Being misdiagnosed as bipolar? Welcome to my world.)

Symptoms I’ve had so far include extremely debilitating headaches, body pains, hives, menstrual cycles from hell, depression, anxiety, IgE allergies, diarrhea, sinus infections, upper respiratory infections, fainting when I stand up (POTS), unshakeable weight gain, eye issues (floaters, itching, etc.), low blood pressure, unexplained irritation and anger, lethargy, exhaustion, insomnia, and probably a few other things I am forgetting. Oh, yeah. Brain fog.

In other words, if you’ve got a laundry list of weird stuff that happens to you, even minor things that happen so often you’ve come to think of them as normal and hardly notice them any more, you might have MCAD. 

If you suspect you do, I’d recommend reading Dr. Lawrence Afrin’s book, “Never Bet Against Occam“. When I read it, I lost count of the number of times I thought to myself “Wait, that’s not normal? I’ve had that my whole life!”

How can I find out if I have MCAD?

It’s tricky. Really tricky. My doctor is one of the worlds foremost experts on MCAD and even he said the tests often don’t show a postitive “your mast cells are whacked” response. He actually clarified that he would be willing to run the tests THREE TIMES before pursuing other testing methods, like bone marrow biopsy.

The tests they’ll run will look for things like N-methyl histamine, prostaglandin D2 or 11-beta- prostaglandin F2 alpha, leukotriene E4 and others, but if you’re like me, that’s all Greek.

What I can say is that I went down to the lab after my appointment, and the tech there needed a full half an hour to prep for my immediate testing. She drew about a thousand vials of blood (seriously, I think it was actually 12 vials) which she immediately wrapped in multiple ice packs secured with rubber bands and raced off to a fridge.

Then I had to go pee in a cup wrapped up in ice packs. That was easy. Right.

Then I had to go back to my friends house and prepare for the 24 hour urine test. That meant filling an ice chest with slushy ice, and submerging one specimen container into the ice completely to the rim. Then, for 24 hours, every time I peed I did so into a container that I immediately shoved as far down into the ice as it would go. Once it cooled, I dumped it into the totally submerged container and shoved it back into the ice to keep it cool for the next time I had to pee.

Then I had to haul the ice chest to the lab, put the specimen container with 24 hours worth of pee into a large ziploc bag filled with ice, race it inside, inform them what I was dropping off and hand it over to a tech who raced it immediately to the lab fridge.

Just think; I may get to fly back to Minnesota twice more to go through that. Fun, fun.

Even better? So far most of my test results have come back normal. Except for a couple that were WAY off the charts. As yet, I still don’t know if I have officially gotten my MCAD diagnosis via testing.

My doctor assured me, after meeting with me, that it doesn’t matter what the testing says. He says I’m “classic MCAD” simply based on my clinical evaluation. So he plans to push through as much testing as possible to verify what he already knows is true.

Why go through all that? What can be done for MCAD?

It sure seems like a lot of unpleasantness to go through for a diagnosis, and believe me, I wouldn’t bother if there wasn’t the chance for a solution!

Unlike FPIES, with MCAD there are some things that can help. And for something as complicated as this condition is, you’ll never believe the first drugs they want you to try.


Claritin. Zyrtec. Tagamet.

I know, right?

Well, those aren’t THE answer. Those drugs don’t always work, and some patients need something with a little more kick. But the doctors start  with those simple, every day, OTC drugs.

Additionally, strict trigger avoidance is always prescribed.

Of course, I’d rather not be drug dependent my whole life, and my friend has proven that, in some cases, you can be healthy and non-reactive without drugs. She’s entered the world of GAPS, properly fermenting foods (so as not to raise the histamine levels), and strict trigger avoidance; a life I wish to emulate.

However, thanks to this summers reaction from hell that won’t go away, I’m so “reactive” that the current plan is to try and get my system calmed down via drugs, and then work towards weaning off the drugs and on to a more holistic method of regulation.

While keeping a fully stocked medical bag. Just in case.

I hope that helped explain what MCAD is to my uninitiated readers. If you’d like to read more about it, click on any of the many links I included in the post, or click on any of the links down below:

Of course, you can always just google “mast cell activation disorder”. That ought to keep you busy for a while!

Fellow mast cell people, did I do the subject justice? What would you share?

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