Mast cell activation syndrome: a review

Area of Science:

• Immunology
• Allergy and Clinical Immunology

Background:

• Mast cell activation syndrome (MCAS) presents with diverse symptoms across multiple organ systems.
• MCAS can be categorized into primary, secondary, and idiopathic subtypes.
• Previous diagnostic criteria involved episodic symptoms, mediator release, and response to anti-mediator therapy.

Purpose of the Study:

• To outline the diagnostic criteria and classification of Mast Cell Activation Syndrome (MCAS).
• To detail the clinical manifestations and laboratory findings associated with MCAS.
• To present a global consensus on MCAS diagnosis and management.

Main Methods:

• Review of existing literature and proposed diagnostic criteria for MCAS.
• Analysis of clinical symptoms, including skin, gastrointestinal, cardiovascular, respiratory, and neurological manifestations.
• Evaluation of laboratory markers such as serum tryptase, urinary histamine metabolites, and prostaglandin D2.

Main Results:

• MCAS diagnosis involves characteristic clinical symptoms, a significant increase in mast cell mediators (e.g., serum tryptase), and symptom improvement with specific therapies.
• Validated laboratory markers include elevated serum tryptase or urinary metabolites during symptomatic periods.
• A recent global consensus integrates clinical symptoms, mediator levels, and therapeutic response for diagnosis.

Conclusions:

• Mast cell activation syndrome requires a comprehensive diagnostic approach combining clinical, laboratory, and therapeutic response criteria.
• Accurate diagnosis and classification are crucial for effective management of MCAS.
• The global definition provides a standardized framework for understanding and treating MCAS.