Systemic autoimmune diseases are themselves a relevant and independent risk factor for atherosclerosis and coronary ectasia. We describe a case of a 58-year-old Caucasian man who was admitted to our department for unstable angina. History of asthma, paranasal sinus abnormality, and peripheral eosinophilia given a high suspicion of Churg-Strauss syndrome (CSS). Diagnosis was performed with 5 of the 6 American College of Rheumatology criteria. The knowledge that CSS is often associated with significant coronary artery involvement and the persistence of chest pain led us to performing immediately a coronary angiography. Coronary angiography showed diffuse ectasic lesions, chronic occlusion of left anterior descending artery with homocoronary collateral circulation from left circumflex artery and subocclusive stenosis in the proximal tract of posterior descending artery. The early recognition of CSS, an aggressive invasive diagnostic approach, and an early appropriate therapy are important to prevent the progressive and permanent cardiac damage in these patients. In the setting of a multidisciplinary approach, careful cardiac assessment is an essential step in CSS, even in mildly symptomatic patients.