Addison's disease presenting with perimyocarditis.

Background: Polyglandular autoimmune syndrome (PGA) and eosinophilic granulomatosis with polyangiitis (EGPA) do not seem to represent a coincidental association.

Case Presentation: A case of a 15-year-old boy is reported who presented with severe systemic inflammation, perimyocarditis and cardiogenic shock, in whom EGPA was initially suspected and later diagnosed with autoimmune adrenalitis with PGA.

Conclusions: The severity of the systemic inflammation and perimyocarditis suggests a more widespread autoimmune-mediated process. Autoimmune adrenal insufficiency should be considered in all cases of pericarditis and perimyocarditis, especially when the severity of clinical manifestations exceeds the expected for the severity of the cardiac findings, as timely identification and prompt treatment may be life-saving.