Wait. We're Taking Pepcid for What Now?

How I accidentally joined the MCAS club against my will.

I’m tired, y’all.

It’s just me over here.

I write and manage this Substack. I research, write, edit, produce, record, and upload the podcast (shout out to the three people who listen). I create all the social media content (a task I rank somewhere between doing my taxes and a root canal). I teach Pilates. I coach clients. And I run a business that, on its best days, feels like it’s being held together with chewing gum, determination, caffeine, and whatever scraps of executive function I can find in the couch cushions.

Some days I can attack a to-do list like a rabid raccoon in a dumpster.

But most days?

Most days I’m dealing with enough fatigue and brain fog that—full disclosure—I could lie down on the studio floor and take a nap halfway through a private Pilates session.

I won’t.

But the thought crosses my mind often, and I have certainly taken a snooze on the Cadillac between clients.

Frequently.

Living with a collection of autoimmune conditions means I’ve spent years learning about all the weird cousins that tend to show up at the same family reunion: POTS, chronic fatigue syndrome, dysautonomia, mysterious inflammatory nonsense, and whatever diagnosis the internet is talking about this week.

The challenge is that many of these conditions share symptoms, have imperfect testing, and often come with the same advice:

Get more rest.

Reduce stress.

Drink more water.

Exercise, but not too much.

Sleep better.

OMFG. As if the people experiencing crushing fatigue simply forgot to try being less tired.

At some point, I mostly stopped trying to solve the mystery. My labs are usually “fine.” My doctors are often reassuring. And yet there are days when my body feels like it’s operating on 17% battery and no one can find the charger.

So I’ve largely accepted that this is the body I live in, and my job is to work with it rather than constantly fight it. The problem, of course, is that “get lots of rest and take frequent breaks” is excellent advice for someone with a trust fund and a personal assistant.

For a one-woman show, running approximately seventeen jobs simultaneously? It’s f*cking impossible.

So instead, I do the thing I always do. Put my head down, take a deep breath, and get back to caring for my clients.

A few years ago, if you’d asked me what MCAS was, I would’ve guessed it was either a new cable channel (Who has cable anymore?), a government agency, or a certification I was supposed to have but somehow missed (the latter most likely).

It turns out MCAS stands for Mast Cell Activation Syndrome. Which is somehow both less exciting and more alarming.

I first started hearing about it from clients. One client had it. Then another. Then another. At first, I nodded professionally and took notes like the competent health coach I try to be. “Interesting. Tell me more about that.” Meanwhile, internally: “These symptoms sound extremely familiar. Dear Gawd. Do I have MCAS?”

The problem with working in wellness is that every few years there’s a new Thing. Adrenal fatigue. Leaky gut. Mitochondrial dysfunction. Histamine intolerance. A mysterious inability to tolerate gluten, dairy, alcohol, fragrance, stress, joy, fluorescent lighting, and the sound of someone chewing. It can be hard to tell which of these represent legitimate emerging science and which ones are wellness culture putting a ring light on normal human suffering.

So, I started researching. And unfortunately, the more I read, the more I had the deeply uncomfortable experience of seeing myself reflected in the literature. You know the feeling. You start Googling symptoms, and twenty minutes later you’re simultaneously convinced you have a rare autoimmune disease and that you’re being dramatic.

So what actually is MCAS?

The oversimplified explanation is that mast cells are part of your immune system. Their job is to sound the alarm when your body detects a threat. Tiny over-caffeinated security guards carrying air horns. Normally, they release chemicals, including histamine, when something dangerous shows up.

In people with MCAS, those security guards seem to have misplaced their judgment. Instead of responding only to actual threats, they start reacting to things like food, heat, cold, stress, exercise, fragrances, environmental triggers, hormonal changes, and — okay, maybe not existing, but honestly, sometimes it feels like merely EXISTING is a trigger. AND. While it has autoimmune vibes, it is not an autoimmune condition.

The result is a weird constellation of symptoms: flushing, itching, hives, digestive issues, headaches, dizziness, fatigue, brain fog, heart palpitations, and anxiety that feels suspiciously physical. Basically, the kind of symptom list that makes a doctor look at you and say, “Have you considered reducing stress?” Which is the part where my clenched fist reflexively twitches because it wants to punch said doctor in the face. Because being told to reduce stress immediately creates additional stress.

What finally stopped me in my tracks was discovering that many people with MCAS are taking Pepcid. As in Pepcid AC. The thing sitting next to Tums at CVS. The medication I have only taken once in my life, after nearly dying (this is not an exaggeration) from scombroid food poisoning—which, while I’m on this tangent, a Venn diagram exists with an intersection of people with MCAS who also have a history of scombroid food poisoning. But I digress…

Apparently, histamine receptors aren’t just hanging out in your sinuses; they’re also in your digestive tract, which means a medication originally developed for acid reflux can sometimes help with histamine-related symptoms. And then I learned people often combine Pepcid with antihistamines like Allegra. At which point I had to sit down. Because if you’d told 25-year-old me that middle age would involve experimenting with a reflux medication and an allergy pill to calm down my immune system, I would’ve assumed you were full of sh*t.

And yet. Here we are.

Then there’s Long COVID. Sigh.

Just when I thought I was starting to understand MCAS, I kept running into another condition: Long COVID. And apparently, these two have been spending a lot of time together. Researchers are still sorting out exactly what’s happening, but there’s growing interest in the idea that Long COVID may trigger or worsen mast cell activation in some people. Which means some Long COVID symptoms end up looking an awful lot like MCAS symptoms…and some MCAS symptoms look like Long COVID. It’s like the f*cking aura bora. Who. Knows!!

This is where my brain started to melt. Because now the question becomes: Do I have MCAS? Do I have Long COVID? Do I have perimenopause? Do I have an autoimmune condition? Am I burned out? Is it just my neurodivergence? Am I just fifty? Or am I simply falling apart?

And also? Do I even care anymore?!

The overlap is honestly ridiculous. Fatigue. Brain fog. Dizziness. Heart palpitations. Exercise intolerance. Sleep disturbances. Random reactions to things that never bothered you before. At some point, you’re standing in your kitchen wondering whether you’re having a “histamine response”, a hormone fluctuation, post-viral inflammation, nervous system dysregulation OR whether you’re just hangry because you forgot to eat breakfast.

The symptoms are real. The suffering is real. But the diagnostic categories sometimes feel like they’re fighting each other in a dark alley while you stand there holding your insurance card, waiting for something to happen.

And honestly, that’s what resonates with me most about the whole MCAS conversation — not necessarily the diagnosis itself, but the recognition. The possibility that maybe we’re not imagining things. That maybe this collection of seemingly unrelated symptoms actually belongs to the same story.

Or maybe we’re all just falling apart. Honestly, at this point I’m open to multiple theories.

Do I actually have MCAS?

Excellent question. I’d love to know.

The truth is MCAS can be hard to diagnose. Symptoms overlap with a lot of other conditions. Testing is complicated. And the internet contains more than enough conflicting information to make anyone question their sanity. As someone who already spends an unreasonable amount of time wondering whether a symptom is meaningful or whether I just slept weird, I’m not sure I needed another rabbit hole.

But here’s what I do know: the more I learn about mast cells, histamine, inflammation, hormones, and the immune system, the more convinced I’ve become that a lot of people (particularly women and queer folx in midlife) have spent years being told their symptoms are random, unrelated, stress, or anxiety.

Sometimes they are. Sometimes they’re not. Sometimes the body is making perfect sense, and we’re just missing part of the translation.

I started out thinking MCAS was one of those obscure acronyms that only existed in medical journals and niche Facebook support groups. Now I find myself standing in CVS holding Pepcid AC and Allegra, thinking to myself, “What’s the worst that could happen if we give this one a try?”

So if you see me in the pharmacy buying allergy medication, reflux medication, electrolytes, magnesium, and reading glasses all at once, just know that I’m conducting science.