We report a case of a 58 years old woman who presented for clinical picture consisting in skin rash, pruritus, astenia, mialgia, with progressive onset during the last month and recently discovered blood hypereosinophilia. The patient was exhaustively investigated and secondary causes for hypereosinophilia were excluded, mainly allergies, parasitic infections, autoimmune and neoplastic diseases. On hospital admission the patient had no symptoms or personal history suggesting cardiac disease. The initial electrocardiography and echocardiography had minimal changes, but cardiac markers such as proBNP and troponin had high values. The clinical evolution was initially good, with moderate dose corticosteroid therapy, but eosinophilia, leukocytosis and cardiac markers continued to increase, followed by progressive cardiac ischemia and ultrasound changes. We considered a rare case of primary hypereosinophilic syndrome with severe cardiac involvement and we switched to high dose corticosteroid followed by add-on therapy with hydroxyurea. Blood eosinophilia decreased, but cardiac markers and ischemia continued to aggravate and unfortunately the patient died due to sudden cardiac arrest, after three weeks from hospital admission. We concluded that hypereosinophilic syndrome with early and progressive cardiac involvement is a severe and difficult to manage disease, with high fatality risk, that requires complex investigations, multidisciplinary approach and prompt therapy.