Has the POTS, hEDS and MCAS "triad" been proven?
Clinical overlap between POTS, hEDS and MCAS has been described, but no common cause and no validated diagnostic triad has been demonstrated.
- 8 sources
- 5 min read
- Clinical review
- Verified 9 November 2026
Key points
- A 2020 critical review judged the evidence for a relationship between hEDS, POTS and MCAS to be insufficient: according to its authors, the studies that propose it are biased or based on outdated criteria [1].
- In 2025, the AGA acknowledged observed associations between hEDS/HSD, POTS and/or MCAS, but stressed that experimental evidence for the biological mechanisms remains limited and evolving [2].
- The AGA states that current data do not support routine screening for POTS or MCAS in everyone with hEDS/HSD; testing should be targeted to compatible manifestations [2].
- A 2025 Canadian review states that these associations have never been demonstrated in patients who unambiguously meet the ECNM-AIM criteria for MCAS [3].
- A 2025 systematic review found no study in which a mast cell disorder, diagnosed by strict criteria, was found in people with POTS or EDS [7].
- An international World Allergy Organization survey (2026) highlights a gap between suspicion and confirmation of MCAS, but it is not a prevalence study in people with POTS or hEDS [4].
Where does the idea of a triad come from?
The limitations of the early studies and reviews
What the AGA said in 2025
The 2026 publications: a further signal for caution
What can and cannot be concluded
In summary
References and level of evidence
- Kucharik AH, Chang C. The Relationship Between Hypermobile Ehlers-Danlos Syndrome (hEDS), Postural Orthostatic Tachycardia Syndrome (POTS), and Mast Cell Activation Syndrome (MCAS). Clin Rev Allergy Immunol, 58(3):273–297 2020. DOI: 10.1007/s12016-019-08755-8. PMID: 31267471.(evidence synthesis)Limitations: Critical literature review, not systematic in the formal sense; few original research articles found. Read: abstract.Declared conflicts of interest: Not reviewed in the part of the source that was read
- Aziz Q, Harris LA, Goodman BP, Simrén M, Shin A. AGA Clinical Practice Update on GI Manifestations and Autonomic or Immune Dysfunction in Hypermobile Ehlers-Danlos Syndrome: Expert Review. Clin Gastroenterol Hepatol, 23(8):1291–1302 2025. DOI: 10.1016/j.cgh.2025.02.015. PMID: 40387691.(expert opinion)Limitations: Expert review by the American Gastroenterological Association; without a systematic review, its "Best Practice Advice" statements carry no formal rating of the quality of evidence. Read: detailed abstract.Declared conflicts of interest: Not reviewed in the part of the source that was read
- Lee E, Picard M. Diagnosis and management of mast cell activation syndrome (MCAS) in Canada: a practical approach. Allergy Asthma Clin Immunol, 21(1):49 2025. DOI: 10.1186/s13223-025-00998-9. PMID: 41272881.(evidence synthesis)Limitations: Practical narrative review based on the ECNM-AIM criteria, adapted to the Canadian setting; test availability varies by country. Read: full text (PMC12639879).Declared conflicts of interest: M. Picard: fees from Novartis, Sanofi, Lundbeck and Celltrion unrelated to this work, associate editor of the journal, investigator in a study funded by Telios; E. Lee: none
- Giavina-Bianchi P, Giavina-Bianchi M, Morais-Almeida M, et al. Mast cell activation syndrome: Global perspectives from a World Allergy Organization survey on knowledge, diagnosis, and access to care. World Allergy Organ J, 19(10):101470 2026. DOI: 10.1016/j.waojou.2026.101470. PMID: 42857128.(observational study)Limitations: Self-reported cross-sectional survey (547 allergists/immunologists analyzed, responses collected March to May 2025); possible response bias; describes respondents' practices, not the prevalence of MCAS. Read: full text (PMC13651491).Declared conflicts of interest: The authors declare no financial conflicts of interest; funding: not applicable
- Valdez JA, Gansert E, Bhuiyan FJ, Sonaiya MS, Ramesh R, Townsend CO, Voelker D, Chiarella SE, Gonzalez-Estrada A. Lack of evidence for increased mast cell activation syndrome prevalence in postural orthostatic tachycardia syndrome and/or hypermobile Ehlers-Danlos syndrome. J Allergy Clin Immunol Pract, 14(11):2728–2730.e1 2026. DOI: 10.1016/j.jaip.2026.08.005. PMID: 42595300.(exploratory finding)Limitations: Short clinical communication; no indexed abstract and full text not accessible: only the title and metadata were checked. Methods, population and sample size unknown; the page cites the title only.Declared conflicts of interest: Not reviewed in the part of the source that was read
- Castells M, Giannetti MP, Hamilton MJ, et al. Mast cell activation syndrome: Current understanding and research needs. J Allergy Clin Immunol, 154(2):255–263 2024. DOI: 10.1016/j.jaci.2024.05.025. PMID: 38851398.(evidence synthesis)Limitations: Narrative review of knowledge gaps and research needs. Read: abstract (full text not accessible from the verification environment).Declared conflicts of interest: Not reviewed in the part of the source that was read
- Farley M, Estrada-Mendizabal RJ, Gansert EA, et al. Prevalence of mast cell activation disorders and hereditary alpha tryptasemia among patients with postural orthostatic tachycardia syndrome and Ehlers-Danlos syndrome: A systematic review. Annals of Allergy, Asthma & Immunology 2025. DOI: 10.1016/j.anai.2025.03.022. PMID: 40185471.(evidence synthesis)Limitations: Systematic review; conclusion limited by the lack of studies using strict diagnostic criteria.
- Yao L, Subramaniam K, Raja KM et al. Association of postural orthostatic tachycardia syndrome, hypermobility spectrum disorders, and mast cell activation syndrome in young patients; prevalence, overlap and response to therapy depends on the definition. Frontiers in Neurology, 16:1513199 2025. DOI: 10.3389/fneur.2025.1513199. PMID: 40352770.(observational study)Limitations: Retrospective, single-center (pediatric cardiology practice, California); 100 young POTS patients aged 9.6 to 25 years, 80% female, 86% Caucasian. Read: full text (PMC12063504).Declared conflicts of interest: The authors declare no commercial or financial relationships that could constitute a conflict of interest