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Background Allergic vasospastic angina (also referred to as Kounis syndrome) is an under-recognised subtype of vasospastic angina in which coronary artery spasm is precipitated by an allergen. This study evaluates the clinical characteristics, mechanisms and management of this intriguing angina subtype.Methods A systematic review of reported cases of allergic vasospastic angina from 1992 to 2022 was performed using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Each case report was then analysed for patient characteristics, presenting signs/symptoms and both cardiac and allergic investigations.Results A systematic review of 393 allergic vasospastic angina case reports revealed a median age of 53 years (64% males), 46% had one or more cardiovascular risk factors with 32% having an atopic history. Most patients presented with an acute coronary syndrome (ST-elevation myocardial infarct in 71%) following exposure to a wide array of precipitating allergens (55% prescription medications), with multiple potential allergic mechanisms including immunoglobulin-E (IgE)-mediated mast cell degranulation, eosinophil-mediated allergic response and other non-IgE mediated mast cell activation pathways.Conclusion Allergic vasospastic angina is an important and under-recognised vasospastic angina subtype, often presenting as an acute coronary syndrome. Diagnosis of this disorder is important since management differs to conventional vasospastic angina with the potential of allergen avoidance and use of allergic response modulating therapies.