See comments section on this page for several graphics on MCAS symptoms.
DISCLAIMER: I am a layperson and person with MCAS, not a doctor, and am not qualified to give medical advice. The following are things I have found through my own research and experience. Individuals' experiences may vary and efforts should always be made to find trained medical professionals to manage MCAS care. This was also largely written pre-2020 so some parts may be out of date.
Please take what works for you, leave the rest -- trust but verify, do your own research, and consult doctors!
MCAS, "Mast Cell Activation Syndrome", is (put simply) a medical issue where part of the immune system (mast cells) are 'overreactive' and cause histamine and other inflammatory processes to fire excessively, causing a host of multi-system symptoms from brain for to GI issues to fatigue to skin issues to breathing issues ... and so on (symptom list and diagrams are availble at the botton of this page). Although MCAS is estimated by researchers to affect as much as 10-14% of the population, the syndrome was only named 5 years ago and the overwhelming majority of health care providers do not know what it is. Furthermore, diagnosis is still an evolving topic among researchers and there is no standard way to get an official diagnosis.
Mast Cell patients present confusingly to doctors because of its multi-system nature. It is highly idiosyncratic and each individual will have different symptoms, though there tend to be commonalities. MCAS symptoms often present as "unlucky" with a number of seemingly unrelated symptoms that are often dismissed as stress or ignored when traditional testing fails to identify the problem. Mast Cell Issues are suspected by researchers to be related or even an underlying cause of many diagnoses of exclusion such as chronic fatigue, IBS and fibromyalgia.
see also : Oh Twist: When to Suspect MCAD
MCAS: When Histamine Goes Haywire
MCAS interview with Dr. Lawrence Afrin
Facebook group full of MCAS resources
from wikipedia:
Mast cell activation syndrome (MCAS) is one type of mast cell activation disorder (MCAD), and is an immunological condition in which mast cells inappropriately and excessively release chemical mediators, resulting in a range of chronic symptoms, sometimes including anaphylaxis or near-anaphylaxis attacks. Primary symptoms include cardiovascular, dermatological, gastrointestinal, neurological and respiratory problems.
Unlike mastocytosis, another type of MCAD, where patients have an abnormally increased number of mast cells, patients with MCAS have a normal number of mast cells that do not function properly and are defined as "hyperresponsive". MCAS is still a poorly understood condition and is a current topic of research.
MCAS also frequently occurs comorbidly with one or both of EDS (link: diagnostic criteria, EDS society) or POTS (link: Dysautonomia International). The causal links are not well understood, but diagnosis can be helpful to understand connections and identify symptoms that we might have come to think were "normal" but actually have explanatory value and can be treated or accommodated in some way.
Other diagnoses you'll want to be aware of due to their similarity and overlap with MCAS are ME/CFS (often known as chronic fatigue) and, post-2020, Long Covid. Long Covid's similarity of and overlap with MCAS, POTS, and ME/CFS has led many to consider whether viral triggers play a significant role in the other diagnoses. As a result of their involvement in Long Covid, these conditions are getting more attention and awareness from doctors than they used to have, and these specialties are likely to become more explicitly broad ("post-viral chronic illness care") in the future. Or at least, that is what my long covid doctor thinks. :)
I do not discuss any comorbid conditions or Long Covid in this document, as it was largely written pre-2020.
"Mast cells release inflammatory mediators and factors known to enhance angiogenic phenotypes, including heparin, heparanase, histamine, metallo- and serine proteinases, and various polypeptide growth factors, such as tumor growth factor (TGF) and vascular endothelial growth factor (VEGF) " (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3412524/)
The process by which Mast cells release these inflammatory mediators is called mast cell degranulation. Mast Cell Disorders is the umbrella term for mast cell isues including (1) having too many mast cells -- rarer, e.g. Mastocytosis -- and (2) Having oversensitive mast cells that degranulate too often/much, in response to a variety of "triggers" (Mast Cell Activation Syndrome, or MCAS).
The following are written with MCAS in mind but some things may also be useful for MCAD generally.
There are a few different pathways to relief with MCAS. The following is my best (and very incomplete) understanding:
- Promote mast cell stability - Several things you can put in your body calm mast cells down and encourage them not to degranulate.
- Treat the symptoms of mast cell degranulation - predominantly by H1 and H2 antihistamines or by increasing DAO.
- Avoid things that cause mast cell degranulation. This will be individual to everyone but there are some resources that can help you figure it out. This includes everything from diet to environmental exposure to regulating hormones.
- Track what you can - I started out taking a google survey I made multiple times a day to track what I ate and symptoms, but that is a bit hard to keep up (though the data is valuable, I had a stronger sense of where I was every day, and it will help me with a dr. eventually). Now I have a log where every time I take a benadryl I log what time, whether I have any suspected triggers (or what I ate prior, environmental stuff, etc).
- (NEW - need to write more info on this) Support the body's pathways for metabolizing histamine and other inflammatory processes - Another aspect of MCAS is that the body is often not handling histamines properly, which can be caused by deficiencies of certain micronutrients etc. DAO is an example of a factor in metabolizing histamine, but there are others.
Quercitin/Bromelain (maintenance) - mast cell stabilizer. Taken on empty stomach provides general support, anti-inflammation. Taken 20 minutes before food can also help with food reactions. I started out with 1 in the morning and felt results within 3 or 4 days, particularly helping with energy levels. Apples also contain some quercitin and are likely to be a safe\helpful snack if symptomatic. Onions also have quercitin.
Vitamin D3 - mast cell stabilizer, inhibits release of prostaglandins - essential supplement , I noticed big improvements in energy and take it year-round.
Chamomile tea (maintenance or rescue) - This is a simple and natural one that helps me tremendously, especially with nausea. Chamomile is a natural mast cell stabilizer and is widely available as tea so that’s a plus.
Magnesium - not a mast cell stabilizer, but magnesium deficiency causes histamine liberation and magnesium also offers support against migraines. Magnesium Oxide is also a great promoter of digestive regularity. Other forms of magnesium have other supportive benefits.
“H1 antihistamines are mostly used to treat allergic reactions and mast cell-mediated disorders. This subtype is further divided into two generations. While the first-generation H1 antihistamines have a central effect and, thus, are also used as sedatives, second-generation H1 antihistamines have less central effects and are used primarily as antiallergenic drugs. H2 antihistamines are indicated primarily for gastric reflux disease because they reduce the production of stomach acid by reversibly blocking the H2 histamine receptors in the parietal cells of the gastric mucosa. “ (https://www.amboss.com/us/knowledge/Antihistamines)
Benadryl (rescue) - the "nuclear option". 1st generation H1, which means it systemically blocks histamine. Takes effect within 30 minutes but only has a half-life of an hour or two. Can cause rebound effects (symptoms worse as it wears off). Also, some MCAS patients respond to the pink dyes in Benadryl so that’s worth watching out for. Ultimately this is the only thing short of EPI that seems to help everyone, but caution is urged since some report the effectiveness wearing down with overuse. I personally use it as a last resort.
Claritin (maintenance) - H1 (2nd gen) antihistamine. Alternatives include Zyrtec, Allegra or any other modern daily allergy medicine.
Tagamet (maintenance or rescue) - H2 antihistamine/acid reducer. I did find H2s (Zantac at the time) helpful and fairly quick acting (though not as fast as Benadryl) and it lasts longer than Benadryl. May have a risk of rebound effects. Many people take H1 and H2 together daily. I also use H2 as a rescue med as it is effective especially for food triggers, and takes effect in 15 minutes. The interaction with stomach acid is also handy as, while I was never aware of acid issues before, I definitely notice when it is time for my H2 dose. Alternatives include Pepsid.
Baking Soda - 1/4 to 1/2 tsp baking soda in water instantly neutralizes acid and has an antihistamine effect. Can be very helpful for acid stomach and some other reactions. Some risk of rebound effect. Note that b/c of the effect on acid it does affect absorption of other drugs, so take alone and use with caution if you think you may need another oral rescue drug like benadryl soon.
DAO (prevention - for hystemic food) - DAO is a natural manager of histamine in the body. You can take it as a supplement, but orally it only really works to manage histamines that are ingested through food, since it doesn’t make it through the digestive tract to elsewhere in the body, so I haven’t tried it.
Vitamin C (promotes DAO systemically) - Since you can't take DAO directly it helps to encourage DAO production in the body by taking Vitamin C. (http://alisonvickery.com.au/vitamin-c-increases-diamine-oxidase/)
Aspirin (rescue) - Aspirin is unique among pain killers in that it has a particular effect on prostaglandins, which are involved in brain fog. It is the only painkiller indicated for help with MCAS. I use this pretty regularly as a fast-acting rescue drug for brain fog and headache and have been pretty shocked at how much it helps. Note that some MCAS patients cannot tolerate aspirin or other salicylates so proceed with caution. If you think you have aspirin sensitivity there is a whole group of salicylate foods you’d do well to avoid also. Another thing to note about prostaglandin is that for people who men`struate, menstruation causes increased prostaglandins, so using aspirin preemptively ahead of an expected period, as well as during, can help ward off increased symptoms.
DIM complex (maintenance) with Calcium-D-glucarate and other helpful compounds - if you experience any correlation of symptoms with menstrual cycle or other hormonal changes, DIM may be something to add on. Its purpose is to promote healthy estrogen metabolism so that your body handles estrogen without producing harmful metabolites. (This straight-up saved me from some really bizarre symptoms e.g. waking up some days with such brain fog and arm weakness I couldn’t even work from home, not being able to sweat, increased dizziness on standing (POTS), etc.) This also contains Calcium-D-glucarate which is considered beneficial for MCAS (don’t remember exactly why). If you don’t suspect hormonal involvement you might try Calcium-D-Glucarate on its own.
-
Swiss Histamine Intolerance List - https://www.mastzellaktivierung.info/downloads/foodlist/21_FoodList_EN_alphabetic_withCateg.pdf - this thing is gold. Food itself, especially as it sits around, has histamine and other amines in it that can set off mast cells. Everyone responds differently and the idea is to eat as many foods as you can tolerate, but this is a great quick reference guide for identifying foods that may cause troubles (and those that are well tolerated by ppl with histamine issues). I try not to eat more than one potential trigger food at a time so that if I have reactions I can pin them down more easily. Easier said than done. But the list helps a lot, especially to identify foods that have a very low risk of causing issues when you are really needing to play it safe. Also, MCAS patients can react to literally anything, so… yeah.
-
Not being stressed out is literally a matter of health - stress is probably a serious medical risk for everyone, and a lot of stressors are out of our control, but with MCAS anything you can do to give yourself space to deal with stressors before they get too serious is a matter of medical necessity. Being selfish and putting your mental health first ends up being a lot easier than trying to cope wth a flare on top of everything.
-
Screw estrogen - estrogen directly promotes mast cell degranulation, and mast cell degranulation promotes estrogen production. This is why many people with ovaries are affected by MCAS, especially starting around 30 when hormones decide to go on a special journey in anticipation of menopause. Lots of soy or other phytoestrogen consumption could be a problem for some; I personally haven’t noticed a difference but YMMV. Any synthetic estrogen in the body is bad bad news for MCAS which rules out several forms of hormonal contraception. Synthetic progesterone (which balances estrogen in the body) can be helpful for some. DIM complex (listed above) also helps with dealing with estrogen triggers.
-
Consider some form of fasting - fasting for even 12-14 hours between dinner and breakfast calms the digestive system, promotes organ health, avoids the natural histamine release (stomach acid) that comes with eating anything, and —perhaps most importantly — means there’s no chance you’re eating anything that sets off your system and get a baseline for how you’re feeling on a given day. Of course, not everyone can tolerate fasting, so like everything it’s very individual.
-
Breathing masks with PM2.5 protection - These are remarkably helpful for any sensitivities related to fragrances, smoke, etc.
-
Be careful about temperature extremes and sunlight - Yes, MCAS people can have allergic reactions to the sun. Heat and cold too. Like every possible trigger YMMV, but good reasons to resist MN insistence on ‘bucking up’.
-
Proceed with caution when it comes to exercise - Exercise promotes mast cell degranulation and provoke symptoms like sweating (excessive or not enough) and blood pressure issues, so forcing yourself to exercise when you’re not feeling good is likely not worth it.
-
Minimize risk/Use the “Bucket theory” - The fun thing about MCAS is that your reactions to things can vary over time and differing circumstances. One way to think of it is that there’s a “histamine bucket” that can gradually fill up and cause issues. The basic principle is that if you are paying close attention to your body’s responses you can tell the difference between a “good time” when you can be more lax about trigger avoidance, versus a “bad time” when one wrong stimulus could send you over the edge,
