When to Suspect MCAD

photo of an Indian Chameleon on a branch by Shantanu Kuveskar

Photo of Indian Chameleon by Shantanu Kuveskar from Wikipedia

The acronym MCAD is the umbrella term for ALL forms of Mast Cell Activation Diseases or Disorders, including the very rare (thankfully) MC Leukemias, followed by the still rare but less so forms of Mastocytosis (several, including cutaneous and systemic), and lastly the newly but most poorly recognized yet most common (and not at all rare we’re finding) form now called Mast Cell Activation Syndrome or MCAS for which ICD-10 codes finally came out in October 2016. (Yay!)

This latter may run as high as 10% of the population we are now realizing. I’ve seen some sources cite as high as 14% and even higher in one case. Not rare at all! Just rarely recognized. Find best articles for your doctors to learn more here on my MCAD resources page.

All forms of MCAD cause what you might call “extra” allergies & sensitivities that your allergist can’t easily test for due to the over-activation of your mast or “allergy” cells which are throughout your body but especially the skin and GI tract – unlike traditional IgE mediated reactions that allergists are most familiar with and what are normally called “allergies”.  Folks with Mastocytosis have too many mast cells in clumps in various places which may also be over-active. Folks with MCAS have normal or lower numbers, but they are still highly reactive and too easily triggered making them very sick still.

You can be just as reactive and go into anaphylaxis from MCAD as from “traditional” *(IgE-mediated) allergies and (IgG) sensitivities, but also to non-protein substances including chemicals like chlorine and fluoride, scents, hormones, exercise, temperature changes, stress, sunlight and vibration to name a few. Yes, crazy making and challenging to live with! And partly why the MCA diseases are so hard to recognize – they drive and/or mimic many other diseases and conditions, much like a chameleon. They’re hard to differentiate and properly diagnose for everybody.

Many people accidentally use the term MCAD to mean MCAS only, and many use the two terms interchangeably. (It doesn’t help they are off by only one letter either.) While technically incorrect, in the end, it’s the inappropriate mast cell over-activation in all cases that is aggravating us and sending us to the doctor (no matter how many mast cells we have and in what shape) so I don’t get too worked up about it.

Anaphylaxis comes in grades by the way, though doctors and EMTs are usually only interested or concerned with the highest levels/throat closing signs since that’s when it can kill you, and is what your school nurses are constantly watching for. Knowing the milder signs/levels can help you stay calm and medicate in time (or get away from a trigger) to help avoid it escalating to that level. (Staying calm really helps.) No two people will have the same course of symptoms when reacting either. Some also react slower than others – we call ourselves “lucky leakers”, vs shockers.

So when to suspect it?

This is accordingly really tricky, as truly no two patients even with the same form will present alike, even in the same family. As we say about some other conditions, it’s truly as individual as fingerprints just like EDS. Thus it is extremely widely varying in nature of onset, course, and response to medications as the brilliant US hematologist Dr. Lawrence Afrin depicts so thoroughly in his new book Never Bet Against Occam (Amazon 2016). (Highly recommended for both patients and doctors to read – both will find it validating in different ways.)

However, there are some common “themes” and experiences I am listing here, noting that this list is by no means official, nor comprehensive, no two patients will experience all of these issues, but most will experience a good handful if I’m on the right track. (This list is not officially endorsed by anyone yet.)

And  yes, it highly resembles Histamine Intolerance, which is a flip-side of the same coin: failure to out-process histamine leading to the signs of excess, vs over-production of histamine from over-activation. And yes, some poor souls may even have both, along with methylation issues lending to even more overproduction. (Try to keep your histamine levels down, both by not adding any from high histamine foods, avoiding triggers – so you don’t produce your own, and making sure you out-process what you do have okay.)

I’m increasingly convinced MCAD-driven inflammation probably underlies a large percentage of ER cases that are diagnosed as “just anxiety” or panic attacks, or angina and heart attacks that show no signs of heart disease. (Do play it safe and get yourself checked out if suspect any heart problem!) Hopefully this list will help folks to know when to suspect it:

  • Easy flushing red, particularly of the “mantle” (upper chest, neck and face, not always 100%), and especially to stress, heat or triggers (including emotional)
  • Hives, especially stress-driven ones, can be large or small and not always all over
  • Urticaria Pigmentosa (persistent hives that fade but never disappear), TMEP, Purpura
  • Dermatographism – aka “skin writing” where you either turn red easily or even get a hive-like whelt (wheal) with a light skin scratch. (Google it for images.) You may notice red indented sock & underwear “tattoos” where the elastic rests on your skin in winter
  • Adult onset or flare-ups of acne
  • Sudden onset diarrhea especially alternating with constipation (often called IBS)
  • Sudden abdominal bloating and swelling (can look “pregnant” when you’re not)
  • Sudden onset of gas and belching
  • Sudden onset nausea, trouble swallowing (rule out comorbid HDCT driven neurological drivers of this), early satiety
  • Tendency to run cold (but can alternate with sudden hot flashes/sweating bouts or run hot also)
  • React easily (are sensitive) to sunlight, vibration, startling, pressure, stress, hot or cold
  • Sensitive to alcohol and molds (the penicillin class of anti-biotics, mushrooms)
  • Reaction to bee stings and iodine contrast dyes, local & general anesthesias
  • Itching of unknown origin, may migrate, often severe
  • Tingling or burning sensation anywhere in the mouth or GI tract (BMS)
  • GERD
  • Tinnitus of all kinds, but especially after eating certain things
  • Variable blood pressure (BP), may run quite high or low on average and can swing widely at times. Some have a spike with anaphylactic reactions, followed by later drop.
  • Angio-edema (swelling) especially that “migrates”, e.g., shows up in different places (lips, eyes, hands, feet), not always in the same place nor due to being upright (gravity-driven)
  • Shortness of breath and asthma like symptoms and outright asthma
  • Hair loss/thinning
  • A persistent non-productive but wet-sounding cough with no identifiable infectious origin
  • Chronic post-nasal drip or rhinitis in the absence of allergies
  • Watery eyes, burning eyes (feeling of granularity or sandiness behind eyelids)
  • Rashes of unknown origin, adult onset acne or acne-like spots (not same as Urticaria Pigmentosa which is a form of cutaneous mastocytosis)
  • Easy nose-bleeds (epistaxis) of unknown origin, easy bruising or bleeding (w or w/o a comorbid connective tissue disorder)
  • Slow wound healing
  • Sudden weight gain or loss in absence of clear driver/cause (rule out lipedema and endocrine disorders)
  • Sudden mood swings, anger bouts or irritability (we call this the “histameanies” in support circles, smile, and thank everyone for tolerating us through them)
  • Cry easily, easily aroused, emotional (look into histadelia)
  • Sudden anxiety or panic attacks followed or accompanied by additional signs of low-level anaphylaxis (skin signs, mucus, etc.)
  • Sudden onset aphasia, or loss of words or speech, slurred speech or “word salad” that clear up after the reaction/stress subsides or with anti-histamines or mc stabilizers (be sure to rule out stroke!)
  • Any and all forms and levels of anaphylaxis which comes in grades. Many are in mild constant low level state with occasional spikes to higher states or rebound events. (Most medical personnel refuse to call it anaphylaxis until it’s the higher level/s however be prepared for some differences of opinion here and try to stay calm.)
  • Sensitivities or anaphylaxis to any and all drugs, fillers, dyes, additives, preservatives, fluoride, chlorine, etc. We can react to any degree to almost anything, truly. (Yes, crazy making for all.) Sometimes it’s not the active ingredient, but a dye or filler. Or the fact you were upset when you ingested it.
  • Esophageal spasms, nutcracker esophagus, especially when stressed
  • Chronic fatigue, sometimes severe, often identical in onset/nature to opioid-induced respiratory depression (many find this in reaction to gluten and dairy) often misdiagnosed with Chronic Fatigue Syndrome
  • Pre-syncope – or dizziness, light-headedness, feeling about to faint (but you don’t)
  • Full syncope – full fainting (less common but also happens)
  • Confusion, sudden trouble with word-finding, sudden memory-loss (check for stroke tho too, time is of the essence and you’d rather be safe than sorry!)
  • Clotting or alternatively bleeding disorders (either direction) that defy normal hematological diagnosis and workup (and treatment)
  • Swollen lymph nodes of unknown origin, not true lymphomas
  • Any other forms of hematologic disorders (strange cell counts/sizes, changes in same) that do not strictly match true workup for similar conditions (e.g. polycythemia in absence of the JAK2 mutation) or don’t respond appropriately to treatment for same
  • Migraines and cluster headaches, hydrocephalus and “corking” driven dysautonomia
  • Low blood volume from 3rd spacing and urinating more than ingesting during reactions (lends to BP drops and very low BP)
  • Kounis Syndrome or signs of it. (Allergy-type driven MI/vessel spasms)
  • Interstitial Cystitis (IC) or chronic UTI’s that don’t resolve easily or at all with anti-biotics (i.e. “sterile” inflammation)
  • Women may notice “flares” of these symptoms on a monthly basis from their cycles, and or during lifetime hormonal changes, especially any time after age 30 from peri-menopause

Again, this list is neither official, nor comprehensive, but is a start for when to suspect these very tricky to diagnose Mast Cell Activation Diseases. A very large dose of patience is in order – very few doctors are up on the the prevalence of the conditions yet even in May 2016 – nor know how to diagnose (very tricky, no single easy test for all) and how to treat (equally tricky: no single easy medication course works for all, and you may react to any and everything including known helpful medications for others – always start low and slow until you know). Generally avoiding stress and high histamine foods (leftovers, ground meats, fish) and taking anti-histamines seems to be helpful on the whole.

Please be very patient, try to log and track triggers for yourself (and then avoid them as able), be mindful of your mood, condition and environment (including temperature and scents) at all times (I can eat chicken when calm but not when stressed or rushed, e.g.), try to eat single ingredients and whole foods vs complex or processed meals to reduce potential triggers and maintain best nutrition. (Some will fare better than others, some even react just to the physical act of eating, laughing, sex, travel etc. – yes, crazy-making as previously stated!)

Common comorbidities include heritable connective tissue diseases (especially some forms of Ehlers-Danlos Syndrome, notably Hypermobile Type or HEDS), Fibromyalgia (often misdiagnosed HEDS in milder form), migraine, high cholesterol (increasingly recognized as a a sign of inflammation and not dietary driven), diabetes, auto-immune diseases of all kinds, CVID and all forms of primary immunodeficiencies (tendency to get sick easily and often), UTI’s, IC, easy bleeding (in absence of von Willebrands) and bruising, APABS (anti-phospholipid anti-body syndrome) and much more. I’d like to suggest the chameleon as our official mascot: I’m starting to appreciate just how many diseases MCAD both mimics, and drives while going unrecognized for what it truly is.

I will add to this list as able. Again, it’s not meant to be comprehensive nor official yet, just suggestive. Consult a savvy allergist to start, followed by a hematologist who is aware of MCAS as well as Mastocytosis if possible.

See my MCAD Resources page for help with educating yourself and your doctors on the matter and consider joining The Mastocytosis Society for additional information and support for all forms of MCAD on and off line. (They offer an Angel Fund waiver if the fee is a problem for you.) Good luck!

18 Responses to When to Suspect MCAD

  1. Rose ogden says:

    This is a very interesting read, I wish it talked more about treatment options

    • Jandroid says:

      Thanks. I suppose I could add some at some point yes sorry. The main approaches involve identifying and avoiding triggers, including foods, meds, scents, environmental (e.g. temp, vibration) or lifestyle (high stress, trauma). And the use of anti-histamines (H1 and H2 blockers) and various mast cell stabilizers as appropriate. Quercetin is a known natural mast cell stabilizer you can get over the counter, but the powdered form is not as effective as a liposomed version such as Neuroprotek. (Google it.)

      Some patients end up on cromoly sodium which is hard to get, may need to be special ordered and may not be covered by your insurance. (Policies vary, check.) And also ketotifen among some other meds. (Leukotrienes, inhalers, etc.) I highly recommend seeing an allergist /immunologist to start, then work your way up to a hematologist /oncologist as needed. (The latter may prescribe meds to counter mc proliferation when warranted for forms of mastocytosis.)

      The problem is, we’re so darn sensitive and metabolize so differently, that no two patients will experience same course of treatment, and it’s all trial and error. Sometimes you may react to a med, but it’s really just the filler in a tablet you’re reacting to, not the active ingredient itself. Many patients find compounding their meds to work better in that case. Again, you can only learn through trial and error sorry.

      Find support here: http://tmsforacure.org

      HTH – Jan

  2. tammy says:

    You mention sensitivity to “vibration”, are you able to expand on just what you mean by that term, and give some examples? Thank you!

    • Jandroid says:

      Yes. Many of us find the vibration from car and plane engines to make us get suddenly drowsy/pass out if not fully react. I passed out on a short hopper flight that used a prop jet back east last time I tried one. (I’m better on the bigger planes so far.) I struggle to drive very far at all and take many safety breaks.

      One fellow patient told me she can’t ride on the back of her boyfriend’s motorcycle – she literally passes out and falls off, yikes!

      I did find that it’s worse whenever I’ve taken an opioid, but it still happens to some degree even when I have none in my system for over a week. HTH.

      • Betty says:

        This is me!!! I can rarely drive for more than 20 minutes without getting very drowsy. Thankfully I rarely have to drive that far and when I do I almost always have a friend or my fiancé who can drive me to the place.

        • Jandroid says:

          It’s nice to know you’re not alone nor crazy huh? We’ve found “our people” 😉

          • Amanda says:

            OMG! For YEARS, whenever I drive and particularly when there’s traffic (i.e. the car is “idling” and the vibrations are more noticeable), I get flushed and have to rush to a bathroom! I thought it was just the car “jiggling” my insides and making everything have to move! Glad to know this is a thing and I’m not just wacky. I actually had to buy a particular type of car that had VERY low vibrations, and now that it’s getting older, it’s vibrating more and making me want a newer one. Hmmm…. thank you!

          • Jandroid says:

            So glad you found “your people”, and know you’re not losing your mind – just your body – or at least a mast cell granule or two! Welcome to the “pool”. Cheers,


  3. Cece says:

    My daughter and I think the Siamese Cat should be the mascot – because the Siamese Cat are very knowingly patient – They seemingly know more than their owners, patiently wait for their owners to figure things out, and they are mysterious. And as patients of this illness, we seemingly know more about ourselves than our doctors, the researchers, and the people around us – like friends and family, patiently wait for them all to finally understand us and give us what we need, and this illness is quite mysterious. Certainly, the Siamese Cat is mysterious, and this illness is mysterious. (and little children afraid of chameleons!) We could just sum it up in that one word – Mysterious! Xx

  4. Amanda sanders says:

    I have been diagnosed with TMEP but also have symptoms of systemic mastocytosis as well. I am seeing an allergist tomorrow. Fairly certain that there will be a skin prick test done will it show any allergies caused by masto? Seems like all I have read online suggest that the testing wouldn’t be useful in cases of mastocytosis. I am so lost and it seems my primary care doc has no clue what to do with me.

    • Jandroid says:

      So a little clarification is in order: Masto itself doesn’t cause “true” allergies which are IgE-mediated reactions. But it can lend to their being heightened in those who have allergies. And… you may find you react to some things >even in the absence of a IgE< lending to the confusion. I'm now convinced my underlying MCAS lent to my increased reactions to the skin prick tests of my youth. (My arms/back would swell up quite huge very quickly, causing them to wipe the serum off!) This comes from having a heightened histamine level over all in our bodies, making us sort of "hair-trigger" ready to react to almost anything. Some people have absolutely zero "true" allergies, that is, zero IgE-mediated reactions, yet are still very sick as though they had "allergies" because of either MCAS or Masto that hasn't yet been recognized. (Yes, TMEP is a form of cutaneous Masto I believe or a sign of at least a form of MCAD.) You may also have some true IgE-mediated "allergies" >in addition< to any underlying masto or MCAS. This just lends to your overall sickness level and reactivity. Does that make sense I hope? All forms of MCAD are rarely recognized, and some not at all yet, so this is often tricky to get allergists to see. HTH!

  5. Kristen Mann says:

    You are my long lost twin! Haha I’m kidding, of course…but I have spent my whole life thinking I am the only person who is really like this. Though I would not wish it on anyone else, it’s exciting to know I’m not alone. You do sound just like me. You describe the symptoms fairly similarly to what I’ve always tried to tell people. Thanks for sharing!

    • Jandroid says:

      Lol – hi twin! And not surprised. 😉 You’re quite welcome, glad you found me. I’m semi-convinced we’re all part of one giant “Clan Dumpty” of Humpty fame, right? 😉

  6. Heidi Corey says:

    I am a nurse who has not been able to work due to severe anaphylaxis. I have had 9 reactions since August. Mostly to fumes and some unknown. Allergist is at his wits end. So I started researching myself. I have Celiac Disease and Adult Stills Disease. For many years I have suffered from severe arthritis, fatigue, unknown weight gain, salmon colored rashes (thought to be from the Stills), chronic diarrhea, GERD, edema, cold alternating with severe hot flashes, burning in GI tract, very sensitive to anything that touches my skin, the feeling of sand in my eyes, wet cough (smokers cough but I don’t smoke), asthma, dizziness, etc. My rheumatologist says that often there are many other diseases associated with autoimmune. I hardly leave my house because I react to everything. I found this site and plan on calling my rheumatologist tomorrow.

    • Jandroid says:

      I’m so sorry for your health challenges, but glad I might be helping you close in on a likely answer. That is a classic story of the path to an MCAD diagnosis – many are diagnosed with “idiopathic anaphylaxis” as the allergists fail to find IgE drivers. We’re finding SO many other ways to trigger mast cells and basophils besides proteins that generate IgE antibodies alas including chemicals (chlorine, fluoride), scents, vibration, stress, pressure and temperature (hot or cold). Definitely check out my resources page for more to help with your diagnostic journey, and settle in – it’s a marathon I’m afraid due to the lack of awareness and updated info in the medical world yet:


      Good luck!

  7. E Wilson says:

    After an anaphylactic reaction due to an unknown food, I finally had allergy testing today and it showed I was only allergic to venom (I’d had an episode due to yellow jackets once a couple of years ago). However, I had an outrageous reaction to the positive control histamine. For the intradermal test, the spot on my arm looked like a quarter with the thickness of a nickel was trying to push its way out of my arm and the lab tech/nurse said the redness was unmeasurable, and would have to be noted as the maximum of 45 rather than the three or so inches it truly was. I asked a lot of questions and she said I basically was allergic to myself by being allergic to the chemical histamine that your body produces. Basically, we’d found our answer, she said. When I mentioned it appeared I was allergic to histamine to the doctor, she said everyone is supposed to react to the histamine. And that was that.

    She had me have blood work done, and I am supposed to go back in two weeks. Should I call her and further explain what happened in the lab? I feel like I came home so empty handed. She did say she expects the blood work to show nothing and suspects mast cell issues, though she seems more mystified, where the lab tech/nurse, though she probably shouldn’t have, felt confident in diagnosing me.

    • Jandroid says:

      Boy that’s a toughie – and an all too common experience I’m afraid, where an allergist is afraid to go out on a limb and recognize a form of MCAD, but a nurse or tech isn’t. I would try bringing her some info, especially this article from Dr. Afrin (if not his actual book) to help her along:


      Which is on my MCAD resources page from which you can harvest all you like here (nay, I recommend it):


      At a minimum, it sounds like you have a high baseline histamine load to get such a large wheal (raised patch at the test scratch site) like that. (Aka “dermatographism” – google it.) I would at least suspect you of a form of MCAD at a minimum. The $64B Q is can you get it diagnosed – even some of the sickest patients struggle to get positive test results, so in the end, as long as a doctor will help treat you presumptively and recognize your symptoms and suffering, you’re just as well off in some ways.

      If she (the doctor I presume) will not, you may need to try to find another. I’d seek support from these guys in the process:


      Hope that helps, good luck!

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