Frequency (prevalence) of MCAD
- General considerations on frequency
- Bibliographical references on the frequency of mast cell activation diseases
It is currently estimated that up to 17% of the population is affected. However, the low level of awareness of MCAD and the lack of an unequivocal diagnostic tool make it impossible to give an exact figure. In general, it is difficult to draw a line between affected and unaffected. Firstly, there are very different degrees of severity, and secondly, the mast cells of every healthy person can also be activated if the triggering stimulus is strong enough.
General considerations on frequency
For the prevalence of mast cell activation diseases (MCAD) in the population different numbers are offered around. But before we believe any figures, we have to ask ourselves whether people can be divided clearly enough into “affected” and “unaffected” people. The difficulties:
Unclear diagnostic criteria, high estimated number of unreported cases
In most forms of mast cell activation (MCA), the exact physical cause is not yet known. Clear diagnostic criteria and meaningful diagnostic methods are still lacking. The level of awareness of the disease among the population and doctors is still very low. If someone has ever heard of mastocytosis, he thinks of a very rare skin disease, as was previously taught, and would overlook the much more common forms of MCA. Therefore, the frequency can hardly be recorded at present and there is probably a huge number of unrecognized cases.
Different degrees of severity
With mast cell activation diseases there are different degrees of severity, from only occasionally slightly affected, who do not notice much of it, to very severely affected (incapacity for work or even need of care). The transition between "affected" and "not affected" is fluid.
External factors (environmental mast cell activation)
The degree of concern also depends on the currently prevailing environmental factors or civilizational "achievements" (eating habits, stress, medication, environmental pollutants, etc.). Basically, the mast cells of every human being can be activated if the stimulus is strong enough (e.g. tear gas). This is just a question of dose. However, a "healthy" person only feels this in rare extreme combinations (e.g. a lot of alcohol, mast cell-activating foods and perhaps an additional medication).
Some are only temporarily affected
Only a few have been affected since birth. Some people develop this mostly acquired disease at some point in their lives, others are only temporarily affected, e.g. during infections, drug or alcohol abuse, drug use, intake of environmental toxins, certain weather conditions, menstrual cycles, etc. Episodic courses without recognizable external triggers are also observed.
Where should one draw the line between the affected and the unaffected part of the population?
Nevertheless, here are some examples of sources with information on prevalence:
Bibliographical references on the frequency of mast cell activation diseases:
- “Bis vor kurzem war es weitverbreitete Ansicht, dass die MCAD zu den seltenen Erkrankungen gehört. Dies trifft allerdings nur fÃ¼r zwei Unterklassen zu: für die systemische Mastozytose und die Mastzellleukämie, deren Prävalenzen mit 1:364 000 bzw. noch mindestens 2 Grössenordnungen geringer berechnet wurden [Haenisch et al. 2012]. Dagegen betrug die Prävalenz der MCAD in der deutschen Bevölkerung in einer aktuellen ersten Studie bis zu 17 % [Molderings et al. 2013]. Diese hohe Prävalenz muss in weiteren grossen epidemiologischen Untersuchungen noch bestätigt werden. Ueberraschend ist diese hohe Prävalenz jedoch nicht, denn sie ist vermutlich Ausdruck des häufigen Auftretens des Mastzellaktivierungssyndroms, das ursächlich verschiedenen häufig auftretenden klinischen Erkrankungsbildern wie bestimmten Formen der Fibromyalgie [...] und Untergruppen des Reizdarmsyndroms [...] zugrunde liegen kann.” [Molderings et al. 2014]
English translation: Until recently, it was widely believed that MCAD is a rare disease. However, this only applies to two subclasses: systemic mastocytosis and mast cell leukemia, whose prevalences were calculated to be 1:364 000 or at least 2 orders of magnitude lower [Haenisch et al. 2012]. In contrast, the prevalence of MCAD in the German population in a recent first study was up to 17 % [Molderings et al. 2013]. This high prevalence has yet to be confirmed in further large epidemiological studies. However, this high prevalence is not surprising because it is probably an expression of the frequent occurrence of mast cell activation syndrome, which can be the cause of various frequently occurring clinical diseases such as certain forms of fibromyalgia [...] and subgroups of irritable bowel syndrome [...].
- “Increasing estimates of prevalence: 1 - 17% of the general first-world population?” [Afrin 2014]
- “The prevalence of MCAD suspected by symptom self-report in first-degree relatives of patients with MCAD amounted to approximately 46%, compared to prevalence in the general German population of about 17% (p<0.0001). [...] The immunoÂhistoÂchemically different subtypes of MCAD (i.e. mast cell activation syndrome and systemic mastocytosis) should be more accurately regarded as varying presentations of a common generic root process of mast cell dysfunction, than as distinct diseases.” [Molderings et al. 2013]
- “Few data are available concerning the prevalence of systemic MCAD. SM and MCL are rare disorders. For SM, data from the French mastocytosis network AFIRMM, the Spanish mastocytosis network REMA, the Italian Mastocytosis Registry, and the German Competence Network on Mastocytosis (own unpublished results; personal communications), suggest a prevalence of at least 1 in 364,000 in Europeans. However, given that these data represent only a proportion of all cases, the true prevalence will be higher. Data from a clinical population suggest that the prevalence of MCL is two orders of magnitude lower than that of SM. In contrast, MCAS seems to be a more common disorder. Evidence has been presented that MCAS may be an underlying cause of various clinical presentations, e.g. in subsets of patients with fibromyalgia and irritable bowel syndrome. Hence, the prevalence of MCAS is likely to lie within the single-digit percentage range.” [Haenisch et al. 2012]
- “[...] we can assume an average frequency for histamine-induced intolerance symptoms within the general population of 5 to 8%, whereby not all of those affected seek doctor's advice.” [Raithel 2012]
Here are some more numbers about incompatibilities in general:
“More than 20% of the population in industrialized countries suffer from food intolerance or food allergy. [...] The majority of cases of food intolerance (15% to 20%) are due to non-immunological causes. These causes range from pseudoallergic reactions to enzymopathies, chronic infections, and psychosomatic reactions that are associated with food intolerance. The prevalence of true food allergy, i.e., immunologically mediated intolerance reactions, is only 2% to 5%.” [Zopf 2009]
References and bibliography
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|Afrin 2014||Lawrence B. Afrin: "The Bulk of the Iceberg revealed: Mast Cell Activation Syndrome". Gastvortrag vom 6. August 2014 an der University of Cape Town, SÃ¼dafrika, ca. ab Minute 0:28:00 des Videos.|
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|Haenisch et al. 2012||Haenisch B, NÃ¶then MM, Molderings GJ.: "Systemic mast cell activation disease: the role of molecular genetic alterations in pathogenesis, heritability, and diagnostics." Immunology. 2012 Sep 7. doi: 10.1111/j.1365-2567.2012.03627.x.|
(There are three types of MCAD: SM, MCA and MCL. SM affects at least 1 in 364,000 Europeans. MCL is two sizes rarer than SM. MCAS, on the other hand, is common (in the single-digit percent range). Mutations that activate mast cells may inhibit other KIT expression cell types. This may explain why individual patients have constipation rather than diarrhea.)
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|Molderings et al. 2014||Molderings GJ, Homann J, Brettner S, Raithel M, Frieling T: "Systemische Mastzellaktivierungserkrankung: Ein praxisorientierter Leitfaden zu Diagnostik und Therapie" [Mast cell activation disease: a concise practical guide for diagnostic workup and therapeutic options]. Dtsch Med Wochenschr. 2014 Jul;139(30):1523-34; quiz 1535-8. doi: 10.1055/s-0034-1370055. Epub 2014 May 6.|
|Molderings et al. 2013||Molderings GJ, Haenisch B, Bogdanow M, Fimmers R, NÃ¶then MM.: "Familial occurrence of systemic mast cell activation disease." PLoS One. 2013 Sep 30;8(9):e76241. doi: 10.1371/journal.pone.0076241. eCollection 2013.|
Frei zugÃ¤nglicher Artikel ("The prevalence of MCAD suspected by symptom self-report in first-degree relatives of patients with MCAD amounted to approximately 46%, compared to prevalence in the general German population of about 17% (p<0.0001). [...] The immunohistochemically different subtypes of MCAD (i.e. mast cell activation syndrome and systemic mastocytosis) should be more accurately regarded as varying presentations of a common generic root process of mast cell dysfunction, than as distinct diseases.")
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|Raithel 2012||Interview mit Prof. Dr. med. Martin Raithel, UniversitÃ¤tsklinik Erlangen: "Exclusive: 10 questions answered about Histamine Intolerance". Erschienen auf der Website Histamine Intolerance Awareness by Genny Masterman. November 2012.|
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|Zopf et al. 2009||Zopf, YurdagÃ¼l; Baenkler, Hanns-Wolf; Silbermann, Andrea; Hahn, Eckhart G.;Raithel, Martin: "Differenzialdiagnose von NahrungsmittelunvertrÃ¤glichkeiten / The Differential Diagnosis of Food Intolerance". Dtsch Arztebl Int 2009; 106(21): 359-69|