Mast Cell Activation Syndrome (MCAS) Related Liver Dysfunction

Pathophysiology of MCAS-Related Liver Dysfunction

• MCAS is defined as a primary clinical condition with spontaneous episodic signs and symptoms affecting at least 2 organ systems resulting from secreted mast cell mediators, according to the Journal of Allergy and Clinical Immunology 1
• Mast cells release inflammatory mediators including histamine, prostaglandin D2, and leukotriene C4, which can affect multiple organ systems including the liver, as reported by the Journal of Allergy and Clinical Immunology 1, 2

Clinical Manifestations of MCAS-Related Liver Dysfunction

• These liver abnormalities may occur alongside other systemic manifestations of MCAS affecting cardiovascular, dermatologic, respiratory, and gastrointestinal systems, as noted by the Journal of Allergy and Clinical Immunology 3

Diagnostic Approach for MCAS-Related Liver Dysfunction

• Diagnosis requires documentation of: recurrent episodes of systemic symptoms affecting at least 2 organ systems, elevated levels of mast cell mediators during symptomatic episodes, and response to medications targeting mast cell mediators, according to the Journal of Allergy and Clinical Immunology 1, 3
• Laboratory evaluation should include: comprehensive metabolic panel with liver function tests (LFTs), serum tryptase level, and urine N-methylhistamine, 11β-PGF2α, and LTE4 levels, as recommended by the Journal of the National Comprehensive Cancer Network and the Journal of Allergy and Clinical Immunology 3, 4

Differential Diagnosis

• Primary MCAS must be distinguished from secondary MCAS, systemic mastocytosis, hereditary alpha-tryptasemia, metabolic dysfunction-associated steatotic liver disease (MASLD), and other causes of liver enzyme elevation, as noted by the Journal of the National Comprehensive Cancer Network and the Journal of Hepatology 3, 4, 5

Management of MCAS-Related Liver Dysfunction

• Treatment focuses on controlling mast cell activation with H1 and H2 histamine receptor antagonists, mast cell stabilizers, leukotriene receptor antagonists, and COX inhibitors, as reported by the Journal of Allergy and Clinical Immunology 1, 2
• A multidisciplinary approach involving hepatology and allergy/immunology specialists is recommended, according to the Journal of the National Comprehensive Cancer Network 4

MCAS-Related Liver Dysfunction Diagnosis and Management

Differential Diagnosis

• The European Association for the Study of the Liver recommends ruling out metabolic dysfunction-associated steatotic liver disease (MASLD), which affects more than 30% of the general population and commonly causes mild transaminase elevation, particularly in patients with metabolic risk factors 6, 7

Management and Monitoring

• The American Academy of Dermatology suggests monitoring liver enzymes every 3-6 months while on treatment to assess response and ensure no progression 8