Anaphylaxis and mast cell reactions

Author’s note: I am not a medical doctor. Anaphylaxis and use of epinephrine must be discussed with the managing provider to determine the best treatment plan for any individual patient.


Determination of mast cell reaction vs anaphylaxis

Anaphylaxis has a very complicated relationship with mast cell disease. Mast cell symptoms and reactions are inherent parts of mast cell disease.  All mast cell patients can reasonably expect to have some mast cell symptoms as part of their baseline.

Anaphylaxis is not an inherent part of mast cell disease. Anaphylaxis is a complication of mast cell disease.  Mast cell patients are at increased risk for anaphylaxis, but not all mast cell patients experience anaphylaxis.  In some studies, as many as 50% of mast cell patients had never experienced anaphylaxis.

The fact that anaphylaxis and mast cell reactions can have the same symptoms is probably the reason why it is difficult to separate the two. So for a minute, let’s stop talking about mast cell disease and consider a similar scenario that is better described.

  • Coronary artery disease (CAD) is the leading cause of death worldwide. It affects millions of people around the world. Everyone knows someone with coronary artery disease.  Probably multiple someones.
  • Patients with CAD have narrow arteries that interfere with blood flow to the heart. When they are diagnosed with CAD, their provider will tell them about symptoms they may experience daily as a normal part of their disease.  Their provider will also tell them about symptoms that they may experience that indicate the heart is not getting enough oxygen, like radiating chest pain, shortness of breath and nausea.  In these scenarios, the patient needs to take a med like nitroglycerin to try and stop the episode.  If that doesn’t work, the patient is at risk for a heart attack.
  • Radiating chest pain, shortness of breath and nausea are symptoms of CAD. Heart attack is not a symptom of CAD.  It is a complication of CAD.  It can also present with the same symptoms of radiating chest pain, shortness of breath and nausea.

Flushing, nausea, diarrhea and hives are symptoms of mast cell disease. (I’m just using these as examples, there are many others).  Anaphylaxis is not a symptom of mast cell disease.  It is a complication of mast cell disease.  It can also present with the same symptoms of flushing, nausea, diarrhea and hives.

These are the potential scenarios when a mast cell patient starts experiencing more severe symptoms than usual.

  1. The patient experiences flushing, nausea, diarrhea and hives. They don’t take rescue meds and the symptoms resolve. This is a mast cell reaction. This is not anaphylaxis.
  2. The patient experiences flushing, nausea, diarrhea and hives. They take rescue meds (not including epi here) and the symptoms resolve. This is a mast cell reaction. This is not anaphylaxis.
  3. The patient experiences flushing, nausea, diarrhea and hives. They may or may not take rescue meds (not including epi here). Either way, the symptoms do not resolve.   The amount of mast cell degranulation triggers a large scale reaction that initiates anaphylaxis. This is anaphylaxis and requires epinephrine. There are two possibilities here: it was anaphylaxis from the beginning, or it started as a mast cell reaction and became anaphylaxis. Either way, it requires epinephrine and other rescue meds.

It seems to me that when anaphylaxis occurs in mast cell patients as a sudden onset event that the symptoms seen are usually distinct from regular mast cell reaction symptoms. (This last sentence is based upon what I have experienced and what is reported to me by patients. There is no data on this.)


General notes on use of epinephrine

How do you know it is anaphylaxis? That’s the hard part. Mast cell experts feel differently about this. Most say to only use epi if you have trouble breathing or low blood pressure because then you know it is life threatening and thus anaphylaxis and not a mast cell reaction.

If you are having trouble breathing or low blood pressure (for adults, under 90 systolic), that is generally cited as the appropriate point to use epi. However, it is a conversation and decision that must be made with you and a doctor that knows you and your disease.

If you have had an episode before where you had severe symptoms and recovered without epinephrine, it is phenomenally unlikely that it was anaphylaxis.

If you think you may need epinephrine and are unsure, it is generally recommended to use your epipen. The reason for this is that epinephrine is pretty safe, despite how the movies depict it. The risk of using an epipen when you don’t need it is side effects of epinephrine use: rapid heartbeat, elevated blood pressure, anxiety, and generally not feeling great for a day or so. The risk of not using an epipen when you need it is death. People die from anaphylaxis with their epipens on them unused.



Meeting diagnostic criteria for anaphylaxis

As I reviewed in the previous post, there are many sets of diagnostic criteria for anaphylaxis. The one that is the most widely used in the WAO criteria published in 2006.  This set of criteria has been validated, meaning it was effective for correctly identifying patients experiencing anaphylaxis while excluding those who weren’t.  Even still, they note that about 5% of patients with anaphylaxis will not be covered by these criteria and to use discretion with this population.

The 2006 WAO criteria (shown below) are often used by emergency departments to determine whether or not epinephrine is needed. If the patient meets the criteria, epi is warranted.  This is one of the reasons why anaphylaxis is often considered synonymous with requirement of epinephrine.


2006 WAO Anaphylaxis Criteria

2006 WAO Anaphylaxis Criteria

Determining whether or not you have anaphylaxis when your blood pressure is not very low and you can breathe fine is not straightforward for mast cell patients. There are several charts that are often posted in mast cell groups that show four or five stages of anaphylaxis.  These charts are designed for people who do not have baseline allergic symptoms.  Mast cell patients have baseline allergic symptoms.

If you have mast cell disease and have flushing, nausea and hives regularly, that is not grade II anaphylaxis. That is mast cell disease.  Symptoms that are part of your normal baseline or reaction profile do not contribute to the overall assessment of anaphylaxis.  So let’s assume I have flushing, nausea and hives every day.  But then one day I also have diarrhea and tachycardia, which isn’t normal for me.  That is grade III anaphylaxis per the Ring and Messmer scale (shown below).  Whether or not you use epi at that point, assuming your blood pressure is not low and you can breathe okay, depends upon whether or not your doctor endorses the use of that scale.


Ring and Messmer Anaphylaxis Grading Scale

Ring and Messmer Anaphylaxis Grading Scale


Anaphylaxis vs anaphylactic shock

I often see people use anaphylaxis and anaphylactic shock interchangeably. They’re not the same thing.

Anaphylaxis is a severe, multisystem allergic reaction.

Shock is more properly called circulatory shock. It is a state arising from poor circulation such that tissues are not receiving sufficient blood supply.  Weak pulse, tachycardia, low heart rate, and mental status changes including loss of consciousness are all symptoms of shock.

Anaphylactic shock is circulatory shock caused by low blood pressure due to the vasodilation from large scale degranulation. By definition, it is blood pressure 30% below the patient’s baseline or below standard values (90 systolic for adults).  So if you aren’t experiencing circulatory shock, you aren’t having anaphylactic shock.



Sampson HA, et al. Second symposium on the definition and management of anaphylaxis: summary report – Second National Institute of Allergy and Infectious Disease/Food Allergy and Anaphylaxis Network symposium. J Allergy Clin Immunol 2006: 117(2), 391-397.

Brown, SGA. Clinical features and severity grading of anaphylaxis. Journal of Allergy and Clinical Immunology 2004: 114(2), 371-376.

Sampson HA, et al. Symposium on the definition and management of anaphylaxis: summary report. J Allergy Clin Immunol 2005; 115(3), 584-591.

Ring J, et al. History and classification of Anaphylaxis. Chem Immunol Allergy 2010: 95, 1-11.

10 Responses

  1. Carol West June 21, 2016 / 3:30 pm

    Thanks again for this valuable information!

  2. Jan Hempstead June 21, 2016 / 3:41 pm

    Wonderful post Lisa! I spend a good deal of time trying to explain to patients that their daily mast cell symptoms are NOT anaphylaxis. I know that you have a great following and mastos listen to you, so hopefully this info will spread. Also, the CAD analogy was perfect! Thank you!

  3. Becky June 21, 2016 / 4:26 pm

    This is very helpful, I have wondered several times about these charts after seeing people saying they are at a grade * anaphylaxis often, and been confused because if that was how it worked I’d be constantly on that scale! If only I had this kind of information from my doctors. Thank you.

  4. Angel June 21, 2016 / 4:56 pm

    This makes so much sense and I never understood it before. I believe I will read it and commit it to memory however I won’t be sharing with basic ER docs. I may know the truth but I like them good and scared thinking my throat could close up at any minute. I need to make sure they aren’t dismissive. So far, mostly they’re petrified. 🙂

  5. Christen June 22, 2016 / 8:35 am

    Thank you for once again sharing important factual information in an easy to understand way. As a nurse and mast cell patient I love reading your blog. P.S. my new PCP reads it to help her better understand how to treat me 🙂

  6. Kathy June 22, 2016 / 8:55 am

    Thanks again for another incredibly helpful post! I have been going round and round about when to epi. It is on my list for my next appointment with mast cell doc. My biggest fear is that I am unable to think clearly when I am having a bad reaction.
    Plus I am terrified of going to the hospital if I ever have to epi. I’m afraid they would make it worse since I react to so many weird things.

  7. Jennifer McCoy June 22, 2016 / 10:47 am

    ❤❤❤ how clear this is to understand! Now if we could only clone you to present to all ER staff physicians, nurses and the entire medical community and have them commit this to memory! We’re all in your debt girl. Thanks again!

  8. Yvonne June 22, 2016 / 11:09 am

    Ditto re everyone above. This is helpful and clearly written. In 2001 I lost consciousness following allergy shots. The lead physician administered an adult dose of epi after which my blood pressure shot through the roof. Pain in the top of my head was horrible. It went back and forth a few times between too high and too low before they got it controlled. They insisted it was not anaphylaxis because I did not stop breathing. Later doctors believed it was anaphylaxis. I carry 2 Epi Jrs, now. Your article helps me understand this from the physician’s view.

  9. Sharon Council June 22, 2016 / 4:11 pm

    Thank you for another informative and extremely useful post. I have been struggling to clearly understand, and explain to my partner, the difference between a mast cell event and anaphylaxis. He asks me at least once a week about how and when the Epi-pens should be used. I will print this and post it on the door of the kitchen cabinet where I keep my meds.

  10. Carrie Denham June 26, 2016 / 6:37 pm

    Lisa– this was an awesome article. Thanks for writing it and sharing! I really benefitted from it: I learned some new things and it confirmed some things for me. Thank You!!

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