What is the frequency of anaphylaxis in Mast Cell Activation Syndrome (MCAS)?

Medical Advisory BoardAll articles are reviewed for accuracy by our Medical Advisory Board
Educational purpose only • Exercise caution as content is pending human review
Article Review Status
Submitted
Under Review
Approved

Last updated: May 28, 2025View editorial policy

Personalize

Help us tailor your experience

Which best describes you? Your choice helps us use language that's most understandable for you.

From the Research

Mast cell activation syndrome (MCAS) can cause anaphylaxis in a significant proportion of patients, with the frequency varying widely among individuals, and approximately 20-30% of MCAS patients experiencing at least one anaphylactic episode in their lifetime, as supported by the most recent study 1. The risk of anaphylaxis in MCAS depends on individual triggers, the severity of the condition, and how well it's managed. Patients with MCAS should always carry emergency medications including epinephrine auto-injectors (like EpiPen or Auvi-Q, typically 0.3mg for adults or 0.15mg for children), antihistamines (such as diphenhydramine 25-50mg), and oral corticosteroids (like prednisone 40-60mg) for prompt treatment of severe reactions, as recommended by recent guidelines 2. Some key points to consider in the management of MCAS and prevention of anaphylaxis include:

  • Identifying and avoiding personal triggers is crucial for prevention, as emphasized in 3.
  • MCAS causes anaphylaxis through excessive mast cell degranulation, releasing large amounts of histamine and other inflammatory mediators that trigger systemic reactions affecting multiple body systems simultaneously, unlike the more localized symptoms that characterize typical MCAS flares, as explained in 4.
  • The diagnosis of MCAS should be considered in the differential diagnosis of patients presenting with recurrent anaphylaxis without a clear cause, as discussed in 5.
  • A personalized treatment approach, taking into account the individual's specific condition, triggers, and comorbidities, is essential for optimal management of MCAS and prevention of anaphylaxis, as highlighted in 2 and 3.

References

Research

Mast cell activation syndrome: Current understanding and research needs.

The Journal of allergy and clinical immunology, 2024

Research

Mast Cell Activation Syndromes: Collegium Internationale Allergologicum Update 2022.

International archives of allergy and immunology, 2022

Research

Mast cell activation syndrome: is anaphylaxis part of the phenotype? A systematic review.

Current opinion in allergy and clinical immunology, 2021

Research

Mast cell activation syndromes presenting as anaphylaxis.

Immunology and allergy clinics of North America, 2015

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

Have a follow-up question?

Our Medical A.I. is used by practicing medical doctors at top research institutions around the world. Ask any follow up question and get world-class guideline-backed answers instantly.