Expanding the Diagnostic Lens: Mast Cell Activation Syndromes and the Hidden Spectrum of Angioedema Associated Mortality in COVID-19

Abstract

COVID-19 related “quorum deaths” may conceal fatal angioedema/anaphylaxis that is misclassified as primary respiratory failure or cardiac arrest, particularly when urticaria or an identifiable allergen is absent. We propose an expanded diagnostic and forensic framework in which SARS-CoV-2–associated endothelial injury converges with mast cell activation disorders and complement system maladaptation, producing a self-amplifying mast cell–endothelium–complement axis capable of terminal vascular collapse without prominent systemic inflammation. To reduce diagnostic indeterminacy and improve cause-of-death attribution, we outline pragmatic postmortem approaches: early serum tryptase sampling, complement studies (C4 and C1-inhibitor levels), targeted histology for perivascular mast cell degranulation in the larynx and terminal pulmonary bronchioles, and selected genetic testing for hereditary angioedema and mast-cell–related variants (e.g., SERPING1, KIT D816V). Integrating these investigations into forensic workflows may reduce misclassification, strengthen pharmacovigilance, and support pandemic-era risk stratification and equity.