The test that ruled out mastocytosis

I belong to a few different mast-cell related support groups, which have been super helpful to me along the way.

From reading posts there, it seems as though it’s far too common for people to end up in a scenario where they have symptoms of mast cell disease, but aren’t sure whether it’s mast cell activation syndrome, or another form of mast cell disorder such as mastocytosis.

And, unfortunately, since there are so few doctors out there who really seem to have experience in treating mast cell disorders, patients in this situation often don’t know where to turn.

So I wanted to let you all know that Dr. Castells was able to order a test for me that really helped to determine that I have mast cell activation syndrome, as opposed to mastocytosis.

Unfortunately, I’m not sure how widely available this test is, as Dr. Catells the only doctor I’ve met who can order it (this was at the Mastocytosis Center at Brigham and Women’s Hospital) but I did want to let you all know that it’s a potential option.

It was a blood test to check to see if your mast cells have a genetic mutation called the KIT D816V mutation.

If you have this mutation, it’s a sign that you have a specific genetic mutation in your mast cells that has been found in patients with mastocytosis.

There can also be a form of mast cell activation that can be caused by this genetic mutation, called primary mast cell activation (sometimes also called monoclonal mast cell activation).

Because my KIT-mutation test came back negative, Dr. Castells was able to conclude that I have secondary mast cell activation– which means that it’s not specifically caused by a genetic mutation, rather it’s triggered by a specific event or another medical condition.

This means, thankfully, that the kind of MCAS that I have is the kind that can actually go away, if you’re able to change the event or condition that triggered it in the first place.

If the KIT-mutation test had come back positive, Dr. Castells’ next step would have been to order a bone marrow biopsy, which can be used to differentiate between the different types of mastocytosis.

Thankfully, the conclusion here was that I have secondary mast cell activation, and did not need the biopsy.

I will be talking more about the different types of mast cell activation in further posts.

For now, here are some references for the concepts I talked about in this post:

Article from the Mastocystosis Society on the three types of mast cell activation.

Nature article on the KIT-mutation



Why I got a diagnosis, even though I don’t fit all of criteria for mast cell activation

I was very lucky to receive a diagnosis of mast cell activation syndrome from my first doctor, Dr. R., because technically, I do not fit all of the criteria for an official diagnosis.

The official criteria to receive a diagnosis actually include the following, as discussed in this article:

  1. Symptoms of mast cell activation: “patients with a presumptive diagnosis of “MCAS” must have two or more of the organ manifestations of mast cell activation such as flushing, urticaria, diarrhea, wheezing.”

I did have this.  I had skin symptoms such as dermatographism as well as flushing and overall itching.  I also had diharrea at times. It was hard to say if I had more symptoms since mast cell activation can also, for example, increase stomach acid and cause acid reflux– which was a problem I already had previously.

2. Lab results that show elevated levels of what are called “mast cell mediators”– these are the chemicals released by mast cells, and when those levels are elevated, it means mast cells are overactive.  Technically, in order to receive a diagnosis, the patient needs to have these high levels documented on two occasions.

As you’ll see in my last post about how I got diagnosed, I was fortunate to be able to capture a high test result for n-methylhistamine in one test.  That one test is what allowed me to be seen as a patient by some of the more sought-after doctors in this area.

However, so far I haven’t been able to capture an abnormal result again, even though I have repeated the tests.

Fortunately, my first doctor, as well as Dr. Castells and Dr. Bayuk, still recognized that something was very clearly going on with me and took me seriously, anyway.

And lastly,

3. The patient experiences an improvement when she takes drugs that inhibit mast cells, or block the chemicals they release.

There are a few different classes of drugs that can be used to treat overactive mast cells, which I’ll discuss in more detail in a later post.   The article explains, “mast cell mediators (such as H1 and H2 antihistamines, cromolyn, leukotriene antagonists) are considered as further supporting evidence of mast cell involvement in the disease process.”

But again– just because you haven’t met all of the diagnosis criteria yet doesn’t mean that you can’t have mast cell activation syndrome.

Dr. R. was willing to give me a diagnosis based on the criteria that I did meet, combined with her clinical judgement.  I think this is one thing I did appreciate about her, even though some of her treatment recommendations did not turn out to be the best.  (More on that later).

As for Dr. Castells, my official notes at Brigham and Women’s say that I am being treated for “symptoms of mast cell activation” and am still working on capturing a second high lab reading to really confirm what my doctors and I already know.  Dr. Bayuk was able to start seeing me and treating me as well.

I think I am very lucky this way, because I have heard stories of doctors who don’t believe MCAS exists, or don’t believe that a patient could possibly have it, if he or she doesn’t fit all of the diagnostic criteria.

I am very grateful that I found doctors who don’t think this way.


Akin, C., Valent, P., & Metcalfe, D. D. (2010). Mast cell activation syndrome: Proposed diagnostic criteriaThe Journal of allergy and clinical immunology126(6), 1099–104.e4.

How I got diagnosed

When I first developed symptoms of mast cell activation in the fall of 2018, I had no idea what was happening to me.

I was already seeing an allergist for my environmental allergies at an outpatient practice here in Massachusetts.

When my mast cell symptoms began, I started to experience some small reactions to food.  My doctor ran blood tests to check for allergies to about 50 different foods, and when they all came back negative, she began to suspect mast cell.

Unfortunately, mast cell disorders were something she’d only ever really heard of in passing… she had not had any training in how to treat it.  (I would later learn that there are only like 3 allergy and immunology fellowship programs in all of the US where mast cell disorders are taught).

She told me I really needed to go to one of the major Boston research hospitals.  After consulting with her supervisor, so she referred me to the allergy department at one of the Boston hospitals which was affiliated with her company.

Obviously, as this is a public blog, I am not going to say anything bad about any of the practices I went to, or the doctors who treated me.

Except I will say that the first place I went was perhaps not the best place for me to go.

My first mast cell doctor

The doctor at the first hospital I went to did have some training and familiarity with mast cell.  However, looking back, I would not say that she really had expertise.  She also had a very negative outlook on managing mast cell patients, and a lot of the things she said made me feel very hopeless about my prognosis.

However, I did need this doctor, Dr. R., to order the diagnostic tests I needed, which would allow me to later be seen by the two doctors who really did help me (Dr. Castells at Brigham and Women’s Hospital and Dr. Bayuk at Allergy and Immunology Associates of New England).

So, I am fortunate that I was able to see Dr. R. at all and get my diagnosis established.

She ordered three tests for me, which you can ask for if you would like to be evaluated for mast cell.

These tests are:

All three of these tests check for substances that are released by mast cells.  When mast cells are overactive, they release more of these chemicals, and so the patient’s levels will be higher.

It’s important to note that, even if you have a mast cell disorder, your test results may not come back positive.

Sometimes it can be a matter of timing– the goal is to catch your results while you’re actually having a flare.  If you’re not in a flare, and your mast cells are not overactive at that particular moment, your test results won’t come back high.

Unfortunately, I have heard stories of mast cell patients struggling for years to get a positive test result, even though they exhibit all of the symptoms of someone with a mast cell issues.  (My understanding is that the truly knowledgeable doctors will still treat patients based on their symptoms).

However, in my case, I was very lucky that my 24-hour urine collection for n-methylhistamine came back high.  It wasn’t crazy high– but it was still above the normal range.

Looking back, although I was devastated when my first doctor gave me these results, she was also able to give me an official diagnosis, and that did allow me to move on to other facilities where I could get better help.

A note:

The tests I listed were what Dr. R. specifically used to diagnose what she suspected was mast cell activation disorder.

However, there are additional tests that can be used to identify other types of mast cell disorders.  (For example, Dr. Castells later ordered a few tests for me that ruled out another mast cell disorder called mastocytosis).

For more on testing, check out The Mastocytosis Society‘s website.

Is the context of when you eat and how you’re feeling, just as important as WHAT you’re eating?

This may be something that’s very individual, but for me…

I have noticed there can be a big difference in how my body responds eating the exact same foods, under different scenarios.

I’ve noticed that if I eat at times when I’m stressed out, or during transition times during the day (like let’s say I’ve been rushing around, stressed, running late for things, dealing with traffic, and then I finally get home).

I am much more likely to get weird bumps on my arms after eating in the second context, not so much the first.

I first discovered this a few weeks ago when I tried beef for the first time.  My dad made me some plain, straightforward ground beef in a pan.  He didn’t even use oil– he cooked it in its own grease.

But I happened to try it at the exact same time that my Mom gave me some really upsetting news about a family member.

Lo and behold, I got really upset, my arm got really itchy, and next thing I knew, it had a few wheals on it.

I thought it was beef that was the problem, and was scared to try it again.  However, I’ve since tried beef a few more times (both in the form of a sandwich at Panera, and also more plain cooked beef at home from Trader Joe’s) and I never got a wheal again.  Which leads me to believe it had more to do with emotional stress.

Last night I came home, again, feeling pretty late, stressed out, and in somewhat of a bad mood.  I was rushing to get my workout (of walking for 15 minutes) done before it was too late at night, and quickly just ate one piece of chicken after that.

Just one piece of Trader Joe’s frozen chicken breast, pan-fried in olive oil.  Which has been one of my safe foods…

Which is why I was SO upset when part of my arm started itching and it looked like I was getting one or two itchy bumps again.

I was really freaked out thinking I might not be able to eat chicken again, but then I thought about what Dr. Bayuk told me at my last appointment.  Which was that the bumps were not about a specific food, but a physiological response to eating.

I’m not entirely sure I agree with this, but since luckily neither he, Dr. Castels, nor Dr. Rashid think the arm bumps sound dangerous, I decided to do an experiment.

Rather than completely freaking out and assuming I can’t eat chicken anymore, I tried to calm myself down.  I read my new DNRS book for a while and watched a few of the recommended videos on neuroplasticity, which made me feel more optimistic about fixing this.  Then I actually fell asleep for a short nap.

When I woke up an hour later, I tried another piece of chicken, and it didn’t really seem like anything too significant happened.  Plus it’s hard to say what could have been a delayed reaction after my body freaked out at the first.

But what definitely did NOT happen was me getting one new, specific, itchy bump.

So, this is something I definitely need to keep in mind.  It’s something Savannah Marcum talks about in her video on MCAS recovery, about how she realized there’s no point in trying something new if she’s stressed out, because the stress itself would totally cloud her actual response to that thing.

It also definitely underscores what Dr. Bayuk said, about it being a physiological response to eating.

So… I’ll be keeping an eye on this, if it seems like I start reacting to my safe foods.  I do think my bad reaction to sweet potato when I tried it may have more to do with that specific food– but, again, I was scared when I tried it, so who really knows.

This whole experience with chicken has really impressed upon me just how integrally linked the nervous system and the immune system are.  Eating the exact same food an hour apart, when I was stressed versus not stressed, seemed to yield entirely different results.

Which is not to say that anyone should expect to totally eliminate ALL stress from their lives.  That’s not possible at all.

But it does give me up hope that, if I’m very careful to pay attention to how I’m feeling, and the relationship between the nervous and the immune system, this may lead to some more clues for healing.

After all, as Dr. Bayuk says, the two are “totally wrapped up in each other.”  The more I learn about it, the more I don’t really think you can separate the two.

(And also thinking back to Jeff’s story over at MEchanical Basis, and how he believes that MCAS is somehow neurological).

I think that makes a lot of sense.

Heyo it’s Mayo– MCAS Series #4- 20 Steps to Healing

Finding this video made a world of difference to me.  I found it at a point when I wasn’t sure if anyone ever really got better from MCAS.

Thank you so much, Savannah, for posting this and sharing your journey.

I wanted to jot down a few notes about what she said because writing is, personally, how I process and internalize things.  So I wanted to write this out, in list form, to really make sure I absorb it.

#1. Build the A-Team.  

I’ve been doing this slowly, but it’s been falling into place.

#2. Make a custom and unique health plan that works for you!

Savannah found that she was not “the average case” because she was having just about ALL of the adverse reactions.  Once she and her team decided to treat her like a 100% unique case, things got a lot better.

#3. Trust yourself 

#4. Genetic testing

I’m planning to ask her where they did this, and what kind of testing they did.

#5. Anti-histamine Medication

I’m not sure if this is going to work for me, because all ant-histamines seem to knock me out.

#6. Low-histamine and low-inflammation food

She cooks all of her food– cooking reduces histamine (?)

She explains it does cook off some of the vitamins, but it’s been working for her.

Local and homegrown produce reduces allergens as well because it’s from the area where you are.

#7. Less is more

Rather than taking multiple supplements, better to eat nutrient-rich food.

She was only able to eat 2 foods at one point.  Added in new foods very slowly.

Identified vitamin deficiencies through testing and added in very pure supplements

Only takes Vitamin C and D

#8. Small and frequent meals

Easier to digest, releases less histamine at one time

was eating a small meal hourly when she was at her worst

bumped it up to every 2 hours

#9. What you put on your body matters just as much.

Body absorbs 70% of what you put on it

switched to all-natural brands

#10 Tweak lifestyle– No stress zone

She realized it was counter-productive to add new things into her life when she was stressed.   Because stress releases histamine.  So if she was stressed, she couldn’t accurately judge if she was reacting to the new thing or not.

#11. Routine

Eat at the same times, schedule appointments at same time, same day

#12. Low stress, low inflammation hobbies

#13. Slow and steady wins the race

#14. MCAS is like PTSD of the body

Like PTSD, have to face triggers in small and controlled doses.

Have to retrain mind and body not to overreact

She and her team plan out her next steps MONTHS in advance so that, by the time comes, she is mentally prepared.

#15. Less is more

Less stress, less chaos, less pills, less ingredients  –> less inflammation, more healing

#16. Good vibes only

Life is no-negativity zone… people places even items of clothes

#17. It is “in your head”

Mindset is everything.  Have to get your mind in the right place.

“I found that training my brain to be and think healthy translated immediately to my bod being more healthy.”

“Everything is connected, so don’t neglect anything.”

#18. Mind, body, soul

Have to heal on every level.  She had to focus on it every single day.

Find something you’re passionate about– fulfill life purpose

Keeps soul aligned and feeling good.

What you put in your body matters, what you put on your body matters, where you take your body matters

#19. Listen to your intuition

Every health decision starts and ends with you

#20. There is no magic instant cure

It is a long process and it was ALL of the steps she took that saved her life.


Thank you SO much Savannah!




MEchanical Basis/Jeff’s Story

This is an absolutely amazing story from a man who became increasingly debilitated over the course of years, following infection with a viral illness.

Jeff went to hell and back, getting progressively more ill over the years.  He had Myalgic Encephalomyelitis (ME), POTS, MCAS, dysautonomia, as well as a host of other symptoms.

Jeff tells his story on his site, MEchanical Basis.

Eventually he discovered that the original virus had damaged the connective tissue in his neck, causing compression of his brain stem through a condition known as Craniocervical instability with atlantoaxial instability (CCI/AAI).

Ultimately, Jeff is the one who had to do the research and go to battle for himself (I’ll let you read his story in his own words).   It is pretty incredible, and heartbreaking what he had to go through just to be taken seriously.

What I’m also taking away from Jeff’s story is that, once he had the surgery to correct this condition and his autonomic nervous system was able to function normally again (in terms of regulating his heart rate, blood pressure, etc)., his mast cell activation syndrome WENT AWAY!

This is incredibly inspiring for me to hear, as I suspect that it was an insult to my own nervous system (in the form of a severe emotional trauma) that started me on this path, and I sometimes wonder if healing from the trauma could make it go away.

It’s certainly not a direct parallel to Jeff’s story, but what I do take away from his story is that, yes, there is absolutely a link between the nervous system and the immune system, and that if something’s wrong with the nervous system, it can throw the immune system off as well.  (And, that by treating the nervous system injury, you can also bring the immune system back into alignment).

Here is one article that Jeff shared on his Twitter feed: it’s a scientific article entitled:

Autonomic Nervous System and Immune System Interactions.

This is SUCH an inspiring story, for so many reasons.  Thank so much, Jeff, for sharing!


Dr. Castells overview on MCAD: presentation to CSF

I wish I could actually go ahead and embed this talk, but here is the link anyway.  It’s an amazing talk Dr. Castells gave to the Chiari & Syringomyelia Foundation a few years ago.

I’d seen this super-informative talk before meeting with Dr. Castells.  However, now that I’ve had an appointment with her and am watching it again, it makes a lot more sense.

Dr. Castells is super, super busy so when you *do finally talk to her, it’s really important to have all your questions ready.

So I’m going to watch this and take extensive notes before I see her again.

Notes and Questions before my next visit:

33:16 Distinguishing between mono-clonal and non-clonal MCAS

Research from Dr. Escribano in Spain:

Urticaria, angioedema, dyspnea –> likely non-clonal

Syncope, presyncope, hypotension –> CKit Mutation –> clonal.  Would need bone marrow biopsy

If my C-Kit is negative, does that rule out a clonal disorder?

23:00 Various medications

Mentions a few things we never discussed:

Ansiolytics (anti-anxiety)

COX-2 Inhibitors for pain (like Celebrex) — she told me at my appointment it was only for mastocytosis?

Medications for subsets of patients:

aspirin for those with high prostaglandins. can be hard to use, desensitize patients to aspirin

anti-leukotrines for those with respiratory symptoms, skin symptoms, swelling of tissues, bronchospasm (like singulair).

corticosteroids only used for mastocytosis

ask her how bad it is to use benadryl often




Dr. Castells on Sodium Cromolyn (Gastrocrom)

In this talk, Dr. Castells describes how the recommended therapeutic dose is 200 mg 4 times a day.  However, the drug causes so many side effects (in the intestines is what she mentions) so they start with 100 mg once a day, and increase over the course of 8 weeks.

Once they get up to the therapeutic level, there is a “profound inhibition of mast cell activation.”

sodium cromolyn = natural “cromone” that she’s been using for 20 years

Dr. Castells’ thought on food activating mast cells

I found this question on the World Allergy Organization website, where it appears doctors can ask questions of other doctors.

Here’s a question I was wondering about, myself:

Does mast cell activation and release occur in non-atopic food intolerance? What is the evidence, for and against?

By Dr Mariana Castells

There is indirect evidence through the measurement of mast cell mediators that GI mast cells can be activated by certain foods in patient with mastocytosis and MCAS. In non mastocytosis patients there is no evidence of mast cell activation in food intolerance which has a wide definition: from lactose intolerance which does not involve mast cell activation and is the result of lactase deficiency to gluten enteropathy which is an IgG mediated immune reaction.


My thoughts:

Need to find out more about this.  What is atopic and non atopic food intolerance, and how does that relate to the strange bumps I get on my arms after eating certain foods?

And do the arm bumps relate to foods that could act more locally to trigger IBS-like symptoms in the GI tract?


Case study from Brigham and Women’s: successful treatment of female patient with MCAS/GI symptoms

This article explains a bit about their work at the hospital in general.  An interesting tidbit:

“Dr. Hamilton is exploring novel treatments for mast cell patients with persistent or refractory symptoms. The primary treatment for the symptoms of mast cell activation remains the blockade of the mast cell mediators with antihistamines, mast cell stabilizers, and prostaglandin and leukotriene inhibitors

The regimen is maximized to therapeutic effect and tailored to address gastrointestinal symptoms. Additional medications with direct action on the gastrointestinal tract such as budesonide are considered based on the clinical presentation.

The use of probiotics and fecal microbiota transplantation are being evaluated as novel treatment modalities in these patients. Finally, dietary intervention including the low histamine diet and FODMAPs diet are offered to patients with particular subsets of gastrointestinal symptoms.”

The article then describes a case study:

“The patient was diagnosed with mast cell activation syndrome and was treated with loratidine, ranitidine, singulair, and cromolyn.


At follow-up evaluations while on treatment, the patient has noted no diarrhea and minimal flushing, sweats, and abdominal pain. Her forgetfulness is also greatly reduced and she is back to her job.”