Today, we’re talking about mast cell activation syndrome and autism — is there an overlap?

I want to start by saying I’m not a doctor. Though I am a Master of Health Studies student, anything I say here and and in my other posts should not be taken as medical advice. If you’re wondering about mast cell activation syndrome, if you’re thinking you might have it, I suggest going to your doctor and asking for a referral to an immunologist.

It’s fairly widely known that autistic individuals usually have some kind of allergy or food intolerance or many allergies and many food intolerances! And the other thing that’s common is gastrointestinal symptoms, gastrointestinal problems. These are so common in autistic folks. Sometimes, these are true allergies and sometimes they’re unexplained reactions that are labelled as intolerances.

One study I read found that about 70% of the autistic people they studied had some type of allergy or dermatitis or rhinitis or asthma, compared to only 7% of age-matched non-autistic people.

When I talked above about how autistic people can often have intolerances — these are called intolerances because they’re not true allergies. Now, this doesn’t mean that they’re any less real or serious than allergies; it just means these intolerances result from different biological pathways than allergies.

To cope with these intolerances, autistic people often just have to avoid the things that they suspect caused their reactions, and unfortunately some people don’t ever make the connection. Maybe they react to just too many things, and so they can’t ever quite pinpoint what it is.

There’s no test. The only thing you can do is try an elimination diet, where you reduce your diet and exposure to almost zero and slowly build up, adding one thing at a time. So if the problem is food, just eat plain rice and then slowly add one ingredient every day. If you react, you can safely potentially say, “That’s what I’m reacting to,” and then try it again to repeat your results, to see if that’s the thing you’re reacting to. It’s best to try elimination diets under the supervision of a qualified healthcare professional, especially if your allergies and reactions are severe.

Unfortunately, there are no reliable, evidence-based tests you can take to test for food intolerances or other intolerances, and that’s why it’s so frustrating for so many people!

Mast cell activation syndrome

Some research indicates that these intolerances or reactions could in fact be an underlying mast cell activation syndrome, or at the very least, just some really hypersensitive mast cells, leaving the person more likely to respond to certain substances in the food they eat or in the products they use on a daily basis.

Mast cells are involved in gastrointestinal problems and in inflammation, and could explain why so many autistic individuals have gastrointestinal problems.

You might be wondering, “What is mast cell activation syndrome?”

It’s a condition where, for whatever reason, a person’s mast cells release their contents way too easily and then when they do, it’s kinda like, blaaahhh, all at once, everywhere! It’s a mess! This release is responsible for the allergy-like symptoms that so many people with this disorder or condition experience.

Since mast cells are located in so many parts of the body — like the GI tract, the skin, the lungs, the bones — it means that the symptoms are often systemic. They cover so much of the body, so it can be so hard to diagnose.

Mast cells are blood cells that are involved in the immune response. Basically, they help protect your body from pathogens. Symptoms of mast cell activation syndrome include itchy skin — with or without rash, edema or swelling right underneath the skin (I get some hecka swelling under my eyes!), skin flushing where it looks like your skin is a bit red and can be on your face or your chest or your stomach, muscle pains, mucus buildup, headaches that are so bad that they almost feel like migraines, difficulty breathing, hives (omg, if I’m not taking my medicine, I can get hives on my face including on my eyelids swelling up to the point of looking like another eyelid!), upset stomach, bloating, diarrhea, constipation, or both diarrhea and constipation, nausea, heart palpitations, low blood pressure, or high blood pressure then low blood pressure, fainting or near fainting (also called syncope or near syncope), hot flashes that are not related to menopause, trouble thinking or focusing, and even chronic pain.

There’s a HUGE list of symptoms associated with mast cell activation syndrome! It’s really annoying!

My diagnoses

As far as my own experience goes, I often had stomach aches and puffy eyes when I was a kid. I would get issues with my stomach and it was not really explained. There were really no reasons for it that we knew of. Potentially stress; I was a stressed out little kid, but the symptoms were there even when things were going well.

Then in high school the symptoms got a bit worse. I started getting really bad insomnia and, looking back, I was definitely reacting to certain things that I was consuming or using, and not really knowing it. At that age, if this was something you were born with and only gradually got worse over time, it just feels normal. You don’t know anything different.

But, it gradually got worse and worse and worse until my early 30s, when I could barely leave the house. My symptoms were so bad. At one point, I was down to around five safe foods, and that was it. I had no idea what was going on.

And doctors were no help, unfortunately. I love medicine and I love healthcare, but doctors were the opposite of helpful. They would often focus on one symptom. “Oh, you have headaches? Let me give you this medication! Oh you have stomach pain? Let me give you Pepto-Bismol!”

Pepto-Bismol, which contains bismuth subsalicylate, is the worst thing you can give someone, by the way, who ends up reacting to salicylates or salicylic acid, which is one trigger that can be seen in mast cell activation syndrome! I didn’t know that then! I ended up in the emergency room that day. It was “fun”!

Once, I went into the clinic because I was having some kind of reaction but had no idea what I was reacting to. There was really no rhyme or reason, because there are so many things that can cause reactions, there are so many things that are potential triggers of mast cells, and everyone is a bit different in terms of what triggers their mast cells.

Anyway, I was reacting to something. Maybe it was seafood. Seafood is bad! High histamines! Whatever it was, it was causing heart palpitations and high blood pressure. At that moment, when I went into the clinic, I had super high blood pressure. It was 160-something over something — it was bad. They waited for a while, and then kept retaking my blood pressure. Finally, they were like, “Listen, your blood pressure is not going down. We have to give you beta blockers.”

I was prescribed beta blockers and I was only 26 or 27 years old. Clearly, my heart was not my issue. But at the time, because doctors are trained to measure and treat symptoms, that’s what they did. Never any exploring the underlying issue. Not many doctors are trained to recognize mast cell activation syndrome. They might be trained to recognize mastocytosis, which is a similar but very different disorder that is when the body creates way extra mast cells. It can be fatal.

Salicylates and histamine

Finally, I went to see an immunologist. He had done a bunch of allergy tests and the tests showed that I was allergic to things that weren’t really shocking. I was allergic to birch, alder, grasses, and that was pretty much it. And then he was asking me, “Go over the last couple emergency visits that you had. What led up to those? What were you doing? What were you taking? What were you eating?”

And then I mentioned the Pepto-Bismol and that it had caused one of the worst reactions of my life. And he said, “Oh! You could be reacting to salicylic acid, or salicylates.”

And that just stuck in my head. That’s all he said. Unfortunately, he didn’t really elaborate much. So I went home and Googled that and I read something that said a person who reacts to salicylic acid or salicylates can also react to naturally occurring salicylates in foods, most commonly in certain vegetables and spices and also certain flavourings and preservatives in packaged food. This was all later confirmed with my immunologist at my next appointment.

At that point, I had already tried doing various elimination-style diets with not much success, and finally I tried eliminating salicylates and when I was reading about salicylates, I also read about histamines in foods. So I went on a diet that reduced both of those things — salicylates and histamines.

Within literally not even a full day or day and a half, I was feeling like a completely new person! Like what?!?!?!

Are we dealing with an entirely separate condition?

Fast forward to seven or eight years later, I get my autism diagnosis. Shortly after that, a few months later, I’m diagnosed with hypermobile Ehlers-Danlos syndrome.

When I’m talking to the geneticist who diagnosed me, I tell her my history of other conditions and other things about me, and she says, “Yeah, you know what? We doctors are recognizing that there’s something interesting going on here. There’s some kind of overlap with mast cell activation syndrome and autism and hypermobile Ehlers-Danlos. This overlap happens so often,” she said, “that there could be some subtype of autism or some kind of condition all its own where these things are co-occurring.”

The other thing she mentioned was POTS — postural orthostatic tachycardia syndrome. I’ve never been tested for POTS. I don’t know if I have it. Maybe I do. I’ve been distracted by other medical things for the last…four decades…

Anyway, these conditions (autism, mast cell activation disorder or syndrome, hypermobile Ehlers-Danlos syndrome, and/or POTS) are so commonly seen together that they could comprise their own single diagnosis one day.

I’m kind of happy about this because it would explain so much. It would explain the fact that when I’m talking to other autistic people, either they have this collection of things (e.g., bendy joints, all the things with mast cells, etc.) or they don’t.

Mast cell activation syndrome is not something that you just get rid of or treat or cure, but there are things you can do to reduce the reactivity of mast cells, beyond just controlling your diet and controlling what products you use. Let me know if you’d be interested in hearing about the things I take and what I do to help stabilize my mast cells.

So there’s all these interesting overlaps. I’m really curious to see what researchers are going to find in the coming years. And I’ll be sure to share what I discover!

If you’d like to know more about this topic, check out:

Mast cell disorders in Ehlers-Danlos syndrome.

Mast cell activation and autism. The first author of this paper (Theoharides) is not a widely trusted source by the autism community or autism researchers in general, but this link is included here because unfortunately Theoharides’s work is some of the only and most widely cited literature on this topic. Theoharides supports autism cure dogma and other dangerous concepts about autism and the autistic community.

Idiopathic mast cell activation syndrome with associated salicylate intolerance.