Mast Cell Activation Syndrome (MCAS): What You Need to Know

Dr. McCann, a pleasure to have you on the show.

Kelly K. McCann, MD (00:10.89)

Thank you so much for having me, Natalie. I'm really happy to be here.

Natalie Tysdal (00:14.36)

Well, your expertise goes a lot of different places. And I've been reading a lot about something I want to go deeper into today because I don't think the general community is familiar with it and how common it is. And that's mass cell activation syndrome. Commonly, if you're seeing it online, MCAS. Can you tell us what it is and who it affects?

Kelly K. McCann, MD (00:38.926)

Absolutely. So let's talk a little biology so you understand mast cells MAST are cells in our immune system and their job is to Hang out at the areas of interface between ourselves in the outside world. So they love the respiratory tract the GI tract they hang out around our blood vessels our skin and their job is to seek out foreign invaders and sound the alarm and

when they see those foreign invaders. And so these are really important for us because they're able to identify toxins or infections. And we want them to do their job and sound the alarm because that's what brings the immune system to the area to help fight those infections or those invaders. But what happens in people with mast cell activation is that their mast cells get a little trigger happy.

and they start sounding the alarm all the time, even when it's something that you're eating regular food that you normally enjoyed, or you're hanging out in the grass and you're rolling around in the grass, or you're smelling a flower, and now all of a sudden your mast cells start sending out these inflammatory messengers we call mediators to things that we would normally tolerate. And so what happens is that people start to develop symptoms.

of intolerance to things that they previously enjoyed, like all of a sudden you start to have a headache after you eat eggs or your favorite dessert or just about anything. People start to develop chemical sensitivities. They can't go down the laundry detergent aisle without feeling sick in the grocery store. A whole myriad of symptoms.

Natalie Tysdal (02:33.272)

So, okay, we understand the biology. Is it more common today? Are we more aware of this than we ever were? Because growing up, I never heard of MCAS.

Kelly K. McCann, MD (02:44.846)

It was actually first written about in the medical literature in 2007. I didn't really start seeing it in my practice, I don't think, until probably 20, I'm sorry, 2014, something like that. But it's been around before then. So there was something called multiple chemical sensitivity that was written about in the 50s and 60s. And there is a strong correlation between

multiple chemical sensitivity and mass cell activation. think that mass cells were probably involved with chemical sensitivity. We just didn't know the pathophysiology at the time. But yes, you're right, Natalie, it is becoming more more common. Pre-COVID, some of the medical literature suggested that the prevalence was about 17 % in the population. That's pretty big. That's one in six people, right?

And now I would say post COVID it's closer to one in four, about 25 % of population. And I think that part of this is because we are so exposed to so many different environmental chemicals now. There are thousands of environmental chemicals that we're exposed to on a regular basis and hundreds of thousands of chemicals in the environment. In addition, geography of Lyme disease is exploding.

you can get a tick bite and, contract a tick borne illness in any state in the country, not just Lyme disease and mold is a huge, driver of mass cell activation. And so we have a concept in environmental medicine called the toxic load, the total load. And we can think about it as our bodies are a sink or our bodies are a bucket. I like the sink analogy because then we have a drain, right? So some people have huge sinks.

and very large drains and they can tolerate a lot of things. So all of the environmental chemicals, all the infections, all of the mold, the EMF, everything that we're exposed to goes into that sink. And if we have a robust detoxification system, our bodies can handle it. But many people have pretty shallow sinks and narrow drains and they can't tolerate a lot of exposures to things and the symptoms show up.

Kelly K. McCann, MD (05:10.094)

when the sink overflows. And I think that that's what's happening. And so just so many things that we're exposed to on a regular basis. I think about plastics that are everywhere, all the chemicals in our personal care products. If we're not pristine about eating organic, we're getting exposed to pesticides on a regular basis. You know, even when we're working really hard and making healthy choices for ourselves, it's hard to...

avoid many of these chemicals, not to mention they're in our air, they're in our water. So it becomes very difficult. And I think that that's what's exploding mass selectivation in the population.

Natalie Tysdal (05:53.763)

Well, and so many of the things that you talked about in the symptoms are probably treated individually, never getting to the root of the real problem. And then you're adding on more problems. Am I right?

Kelly K. McCann, MD (06:00.064)

Yes.

Kelly K. McCann, MD (06:05.998)

That's that's exactly correct. So, you know, people and this is how medicine is is set up to you have a headache or a migraine and you go to the neurologist, you have gastrointestinal symptoms, you go to the gastroenterologist, you have palpitations, you go to the cardiologist, and nobody's looking at the whole picture and saying, well, you have all of these things because you only have 10 minutes to share your story. Right. So this is where functional and integrative medicine is so much more

capable of identifying that these issues are going on for somebody and putting the pieces together.

Natalie Tysdal (06:44.334)

What do you do if someone says or someone's hearing this and they're wow, I've got all of those symptoms, but I'm I'm taking medicine for headaches and I'm I'm careful about this or I take this. How do you get this diagnosis? Are there people who specialize in it as a primary care doctor where you would recommend? I see you shaking your head for anyone listening. They're thinking they're not seeing that. So many people don't know where to go first.

Kelly K. McCann, MD (07:06.478)

Yes.

Kelly K. McCann, MD (07:13.888)

Right. And that is definitely tricky. You would think that if you had a lot of allergic symptoms and a lot of other things, you could go to an allergist or your primary care doctor. But unfortunately, conventional medicine is not, is not really geared towards helping people with these complex issues. And even if you only have symptoms in, you know, three or four systems of the body, they still might miss it.

Whereas if you seek out a functional medicine practitioner, they're going to be much more likely to look at the whole person and be able to see these patterns of multiple systems having an inflammatory response or an allergic response and be able to clue in to the possibility of that diagnosis. Yes.

Natalie Tysdal (08:05.635)

Yeah. I want to take a second because you're an MD. You also practice functional medicine. Is that very common? I see that as a health journalist a little bit more now. But why did you decide to go that direction?

Kelly K. McCann, MD (08:21.538)

You know, unlike many of my conventional colleagues, I always wanted to practice holistic medicine. My original goal when I decided I wanted to go into healthcare was I wanted to be an acupuncturist. And my parents talked to me about this and they said, well, why don't you think about medical school? And I said, okay, I'll apply to medical school. And if I get in, I'll go. And if I don't get in, then...

I'll be free and I'll be able to go to acupuncture school. And I got into four medical schools and I had to go in hindsight. I'm very grateful that I did, but I always had this holistic mindset. No, you know, so in medical school, I was in the, you know, holistic medical student association. And I learned about, I took public health classes and I learned about massage and Reiki and, know, I,

and healing touch, I always wanted to do this more holistic view of things. And so after I graduated, went on to residency, I made sure that I went to a residency that was going to allow me to pursue these things. I had a continuity clinic with a medical physician who did acupuncture. And then soon after that, I did the fellowship with Dr. Andrew Weil at the University of Arizona in Arizona.

in their program of integrative medicine. And so really learned a lot of the foundations of what is aerovado, what is, you know, what is the system of acupuncture? What is chiropractic? Let's talk about supplements and, and diet and, know, using all the tools, right? All the different tools. so that's how I got into integrative and functional medicine. And, and I do think, thankfully now many, many more people are waking up to the idea that

We can't keep giving a pill for every ill. It doesn't work that way. People don't get better. And so I think a lot of more, I'm hoping that more conventional doctors will start to wake up to the fact that functional medicine is the really only way to practice medicine.

Natalie Tysdal (10:37.689)

We are seeing it more and more. mean, there are many offices that have both, or at least are willing to look into the root causes instead of just giving a pill for the ill, as you mentioned. So let's get back to MCAS. And if someone is hearing these symptoms and thinking that might be me, and they go to their primary care that might not be functional, will the primary care say, yeah, that's not existent, or I'll look into that, or do you advise they?

seek out a different type of doctor? Is it becoming more accepted as a diagnosis?

Kelly K. McCann, MD (11:12.414)

It is it is an ICD 10 code you can make that diagnosis there there is an issue though just like with the controversy for chronic Lyme disease is it is it you know a real infection or is it just post Lyme syndrome as touted by the CDC and the international. Sorry that the ISDA which is the infectious disease Society of America.

they don't believe in chronic Lyme and oftentimes there is a divide with MCAS between the allergist who are very strict in their criteria. So there's a blood marker called tryptase and according to the allergy, we call them consensus one people, the allergist and immunologist. If you don't have an elevated tryptase above a certain amount, there's some like

math problem When people are in a flare that has to be 20 times higher or 20 % higher blah blah blah That's their definition if you don't meet that criteria you don't have MCAS as far as they're Consensus to physicians which would include people like dr. Lawrence affrin dr. Theo theoheredes these are the folks that

are writing about and teaching about mass activation really the vanguard of bringing this condition to the forefront were in the consensus to category which is a clinical diagnosis so massive activation is considered a multi system multi symptom allergic inflammatory and growth condition so if people have.

you know, four or five symptoms systems in the body, their neurological system, psychiatric system, cardiac system, GI system, skin, etc. immune system that are inflamed or allergic, that meets the criteria. And you don't even have to have any laboratory values to make that clinical diagnosis, although it's always helpful. But the labs

Kelly K. McCann, MD (13:33.47)

look at the mediators and in commercially available labs we have about maybe a dozen markers that we can look at and there are hundreds if not thousands of mediators in the body. So the possibility of getting a positive test for everyone is pretty low, right? So we have to use clinical observations to make the diagnosis.

Natalie Tysdal (14:02.094)

Okay, so I want to leave time here to talk about getting better. For someone who has the diagnosis, what do you do? How do you treat them?

Kelly K. McCann, MD (14:15.598)

There are two major things that we have to do. We have to calm down the symptoms and then we have to identify what are those buckets? What are those root causes that are dysregulating the immune system to begin with? And the symptom, getting the symptoms better, there are a variety of different supplements, medications, things that can be given to help either block the mast cells from

as releasing their mediators or potentially blocking the mediators from acting. like H1 blockers, histamine blockers, this is your Zyrtec, Zizal, Allegra, Claritin, those are easy to take. And if people are having elevated histamine reactions or elevated histamine levels in the body, you can take an antihistamine and that will help calm down some of the symptoms.

it won't calm down other symptoms, won't block other mediators, so then oftentimes we need other things. But there are dozens of other medications and or supplements that can be helpful. We also really encourage people to focus on their nervous systems. So the nervous system is also involved as well. When people are stuck in fight or flight, or freeze, you know, a stress response that also sends

cortisol, triggers mass cells that lead to the inflammatory cascade. so learning different techniques to calm down the nervous system is critically important for healing and getting symptom relief. These can be Vegas nerve devices. These can be, limbic system retraining or different kinds of brain retraining exercises or programs to help people navigate and learn how to

reduce their their stress response, essentially. And then the last piece and the most important, I think, is as people start to feel a little bit better as we're reducing their symptoms and regular how helping them regulate their nervous systems, then we're exploring what are those root causes? Is it mold? Are you in a moldy house? Do you have a

Kelly K. McCann, MD (16:40.952)

pesticide exposure Are there other kinds of exposures? Did you just put enough? You know was a 5g tower just put in front of your house Do you have underlying Lyme disease or Bartonella Bartonella is cat scratch fever That's even more common than Lyme disease and it's worse in terms of symptoms for a lot of people and very few people talk about Bartonella so as a functional

practitioner, we're looking at these root causes and trying to understand which ones are relevant for the person. Is it a post COVID thing? But for me, the biggest drivers for mass activation are mold, Bartonella and Lyme and EMFs. Huge, huge drivers for people.

Natalie Tysdal (17:32.056)

So of those people that you've treated with this, how much success have you seen once you can reduce those symptoms and start some repair and recovery? Do they live pretty normal lives?

Kelly K. McCann, MD (17:43.362)

You know, I think that some people can get to the point where they live completely normal lives. I think that through the process, they also learn what is really healthy for them. And so they actually don't get their lives back. They become a more healthy, vibrant version of themselves, right? Because part of the reason why the nervous system is off is because

they may not be living their truth. Part of the reason that they got in this situation to begin with maybe because they were living in a moldy house and didn't know it. So what we find is that through the journey, people start to find their their most ideal diet for them.

hopefully it's not terribly restricted, but they make, they're making healthier choices, right? Because they recognize that if they eat like crap, they're not going to feel good. so I think not only is there hope out there for people, but it's an opportunity to really embrace the circumstances that they find themselves in and to recognize that they

they will be better versions of themselves. You know, I have so many stories, but one woman who had mass activation and she had a condition called POTS, postural orthostatic tachycardia syndrome, she couldn't even sit upright for our hour intake because her heart rate would spike so high. was in the one forties when your heart rate is beating at 140 beats per minute. You cannot perfuse your brain. So she had to actually like

lay down in order to finish her up first appointment with me because her heart rate was so high sitting up because she was on a moldy house and her muscles and her nervous system were just on fire. And you know, it's taken some time, but fast forward to two and a half years.

Kelly K. McCann, MD (20:04.04)

She has lost 40 pounds. She is exercising on a regular basis. She has her full-time job and she's very happy and her life is just such a different place than she was when she came in. And she, she didn't know what to expect. You know, she had had this diagnosis for 10 years before she found me suffering. and, now she's got this incredible life that she loves.

Natalie Tysdal (20:33.275)

That's a great story. are these, when someone is diagnosed, and I hear pots often in conjunction with MCAS, is that correct?

Kelly K. McCann, MD (20:42.53)

Yes, it's common. We call it the Pentad patient. they can also often have, so it's the MCAS, the POTS, they can have hypermobility syndrome or LR Standler syndrome where their joints and their connective tissue are more lax. They often will have an autoimmune condition and sometimes have gastroparesis or difficulty with their.

mobility of the digestive tract, will then manifest in gastrointestinal symptoms, small intestinal bacterial overgrowth or small intestinal fungal overgrowth, which then causes its own host of symptoms. So yes, they tend to cluster together.

Natalie Tysdal (21:26.449)

When someone is diagnosed, do they have these conditions for life? Or do you say 10 years later I still have MCAS or does it actually go away? is it lifelong?

Kelly K. McCann, MD (21:41.162)

You know, I don't I don't know how I would think about that, like the connective tissue stuff. That is a genetic predisposition. But what happens is in MCAS is that the hypermobility can become exaggerated, because the mass cells also produce enzymes, right. And so the enzymes degrade the connective tissue. So as people get better, they may still have some sensitivities like

I was I've been exposed to mold multiple times. have have been diagnosed with Lyme and Bartonella. And, you know, I still have some low level allergies that I manage, you know, and, and some food sensitivity. So I don't eat gluten and I don't eat cow's milk, dairy, and I don't eat almonds. But otherwise, I live a pretty healthy life. So do I feel

held back in any way. No, I actually make healthier choices for myself as a result and I think that many of my patients would say the same.

Natalie Tysdal (22:48.933)

The best advice that you would have for someone who thinks this could be them or someone they know. I know you're in California, you do some telehealth, but what would you say to people? How to get help?

Kelly K. McCann, MD (23:01.804)

I'd say the first thing is to really honor yourself and pay attention to that little voice inside because

Kelly K. McCann, MD (23:15.39)

that voice is the one that's going to keep you safe. That voice and your intuition is with you and always supportive of you. That is your fire to help you seek out and find the people that are going to help you get better. So always maintain that connection with yourself and then honor it. If you walk into a doctor's office and they

Don't believe you don't listen to you get up and walk out. Right. It is not worth your time energy or money to stay in a situation where you're not getting the help that you need. Many of my patients like the young woman that I mentioned she listened to podcasts she went on forums she you know she did her research. So do the same listen to podcasts go research. There are a number of

professional organizations that will train providers. So the Institute of Functional Medicine, for example, is a wonderful organization that train functional medicine providers. And that being said, as much as I love them and have, you been part of their training, they are like the next level after residency and fellowship. If you want somebody who is really

Great, and you have a complex case. I would look at two different organizations. One is called the American Academy of Environmental Medicine. This is a professional organization that's been around since the 60s. And these are the doctors who were taking care of people with multiple chemical sensitivity before MCAS ever came into existence.

I consider them the grandfathers of functional medicine, right? And then the International Society of Environmentally Acquired Illness or isei.org is another organization of which I was on the founding board. And they train practitioners in these complex chronic illness issues. So those would be the two places that I would look predominantly. And if you can't find somebody in your area,

Kelly K. McCann, MD (25:41.614)

Naturopathic physicians also can be a good resource depending upon which state you're in. They're not licensed in all the states.

Natalie Tysdal (25:50.258)

I think it's really important. It's what I emphasize too. I've learned to ask questions over three decades and it has made a big difference. So for everyone listening who might think I don't have the answers to listen to that intuition, to find the answers. We have the ability to ask more questions, find a new person, but not to give up if you're not feeling well. Thank you so much, Dr. McCann. I appreciate your knowledge and everything that you've shared with us today.

Kelly K. McCann, MD (26:18.668)

You're so welcome, Natalie. Thank you for having me.