Background: Kounis syndrome (KS), or allergic acute coronary syndrome, describes the concurrence of acute coronary events with hypersensitivity reactions. It remains underdiagnosed, particularly in patients without conventional cardiovascular risk factors. Case Report: We describe a 28-year-old male with no prior cardiac risk factors who developed severe anaphylaxis and acute left ventricular dysfunction immediately after receiving intravenous piperacillin-tazobactam (4.45g). Electrocardiogram showed biphasic T-wave changes, and echocardiography revealed severe global left ventricular systolic dysfunction (ejection fraction 15-20%). Emergency coronary angiography demonstrated normal epicardial coronary arteries. The combination of acute chest pain, ECG abnormalities, echocardiographic dysfunction, normal coronaries, and a temporal link to anaphylaxis confirmed the diagnosis of Type I KS. The patient improved with aggressive resuscitation, antihistamines, corticosteroids, cautious use of epinephrine, and supportive cardiac care. Conclusion: This case highlights the clinical significance of KS in the differential diagnosis of acute coronary syndromes precipitated by allergic reactions, especially in young individuals without cardiovascular risk factors. Early recognition and appropriate management are crucial, especially in young patients presenting with cardiac symptoms during anaphylaxis.