Unstable Angina, Allergic Angina, and Allergic Myocardial Infarction

To the Editor: Nonocclusive thrombus on preexisting plaques, dynamic obstruction, progressive obstruction, inflammation and/or infection, and secondary unstable angina seem to be the 5 not mutually exclusive causes of the unstable angina syndrome. These were suggested in the excellent editorial by E. Braunwald.1 In this editorial, it was pointed out that vasospastic angina, which is a form of unstable angina, is rarely caused by allergic reactions via mediators such as histamine or leukotrienes acting on coronary vascular smooth muscle.We have suggested that the coincidental occurrence of chest discomfort with characteristic clinical symptoms, signs, and …