Table 2 Differential diagnosis of myocarditis associated with peripheral eosinophilia

DRESS associated eosinophilic myocarditis

Temporal association with drug exposure, eosinophil-rich cutaneous manifestations

Eosinophilic granulomatosis with polyangiitis

Asthma, sinusitis, neuropathy, potential lung/renal syndrome, eosinophilic rich granulomas, positive p-ANCA test

Autoimmune myocarditis

Pre-existing autoimmune disorder (e.g., systemic lupus erythematosus), positive antinuclear antibodies (ANA) or extractable nuclear antigens (ENA) serologies, less conspicuous eosinophilia

Infectious myocarditis (parasites/protozoa/viruses)

History of recent viral infection or vaccination or specific exposures in endemic areas (e.g., travel to Latin America for Chagas disease), specific serological testing or viral/bacterial/parasitic PCR

Clonal hypereosinophilic syndromes

Persistent eosinophilia not responsive to steroids, evidence of organ involvement, bone marrow biopsy with pertinent molecular cytogenetic work-up: FIP1L1-PDGFRA or PCM1-JAK2 fusions, PDGFRA/B, FGFR1 rearrangements, KIT mutations