Mast cell disorders Venn diagram

This Venn diagram conceptualizes the relationship between different disorders that involve mast cell activation. The most general category consists of all disorders that are associated with mast cell activation, such as chronic spontaneous urticaria/angioedema, allergic reactions and anaphylaxis due to known allergens (foods, pollens, venom), and allergic asthma. MCAS is a rare and specific disorder in which patients (1) have signs and symptoms consistent with mast cell activation involving at least two organ systems, (2) have evidence of systemic mast cell-mediator release, and (3) respond to medications that counter these mediators. MCAS may be triggered by allergen-specific immunoglobulin E, physical factors, and medications. IMCAS is the same disorder without an identifiable allergen or other specific trigger. Patients with IA are a subset of those with IMCAS who fulfill the diagnostic criteria for anaphylaxis. Clonal mast cell disorders can present similarly to the other disorders of mast cell activation, but they are not idiopathic, because patients have a clonal mast cell population.