“…Inclusion criteria for the patients were as follows: Diagnosis of cross-hypersensitivity ( Pérez-Alzate et al, 2017 ; Blanca-López et al, 2018 , Blanca-López et al, 2019 ) by clinical history and a positive drug provocation test, for one or more of the following NSAIDs: ibuprofen, diclofenac, aceclofenac, indomethacin, naproxen, piroxicam, meloxicam, lornoxicam, celecoxib, and metamizole. ASA-positivity was included as a requisite in the diagnosis because in cross-reactive (non-allergic) hypersensitivity patients react to all strong COX-1 inhibitors, including ASA, whereas allergic hypersensitivity patients tolerate ASA ( Kowalski et al, 2013 ; Pérez-Alzate et al, 2017 ; Angeletti et al, 2020 ); besides, CYP2C9 plays a role in ASA metabolism ( Thiessen, 1983 ; Hutt et al, 1986 ; Bigler et al, 2001 ; Palikhe et al, 2011 ; Gómez-Tabales et al, 2020 ). Patients who presented with hypersensitivity triggered by other NSAIDs whose metabolism is not mainly catalyzed by CYP2C enzymes (including clonixinate, dexketoprofen, ketorolac, etofenamate, ketoprofen, piketoprofen, propifenazone, phenylbutazone, aminophenazone, acetaminophen, etoricoxib and oxyphenbutazone) were excluded from the study.…”