Supplementary Material for: How Can We Better Classify NSAID Hypersensitivity Reactions? – Validation from a Large Database

Background: Hypersensitivity to nonsteroidal anti-inflammatory drugs (NSAIDs) is one of the most common drug hypersensitivities. Several clinical subtypes have been distinguished depending on symptomatology (respiratory, cutaneous, anaphylaxis), timing (immediate, delayed), underlying chronic disease (asthma, chronic urticaria) or putative mechanism of the reaction (allergic, nonallergic mediated). The aim of the present study was to better classify the many hypersensitivity reactions to NSAIDs. Methods: In the present retrospective study, during an 11-year study period, we collected data from all patients with a proven NSAID hypersensitivity. Reactions were classified according to clinical patterns, chronology, underlying diseases and the results of oral provocation tests into 5 and 7 groups in line with two published classifications, respectively. Results: Forty-nine and 88 out of 307 reactions (in 122 patients) could not be classified on the basis of the two previously published classifications. We created a new classification which could include all patient reactions. Conclusions: Our new classification is more suitable for clinical expression of NSAID hypersensitivity. It allows clinicians to identify patients at a high risk, based on the clinical history and clinical manifestations. Moreover, it is helpful for a better understanding and teaching of these reactions.