An unusual case of two acute coronary syndrome episodes caused by allergic and non-allergic coronary artery dissection with potential coronary vasospasm association: a case report.

Background: Type I variant Kounis syndrome is characterized by coronary spasm following an allergic or anaphylactic reaction. Coronary spasm is also recognized as a contributing factor in spontaneous coronary artery dissection (SCAD). Case summary: A 46-year-old woman presented to the emergency room with a chief complaint of chest discomfort following the ingestion of a steamed bun. A marked decrease in systolic blood pressure and a prominent rash on her forearms and groin suggested anaphylactic shock. Upon stabilization of vital signs, acute coronary syndrome (ACS) was suspected based on electrocardiogram findings and symptoms, prompting an emergency coronary angiography (CAG). The CAG revealed severe stenosis with coronary artery dissection in the right coronary artery (RCA), and a stent implantation was performed. Given the suspicion of type I variant Kounis syndrome, a spasm provocation test was performed, yielding a positive result. Six years later, she experienced chest discomfort while sleeping and was admitted to our emergency department. An electrocardiogram showed ST-segment elevation in leads II, III, and aVF. An emergency CAG identified a severely stenotic lesion with coronary artery dissection in the RCA, leading to a diagnosis of SCAD. Direct stenting was performed at the stenotic site. The patient was discharged following intensification of medication. Discussion: This report describes a rare case of a middle-aged woman with two episodes of ACS caused by both allergic and non-allergic coronary artery dissection. These episodes suggest that a shared underlying coronary vasospasm in both conditions may be a common trigger for coronary artery dissection.