Methods used for diagnosis
The median time interval between the reaction and the study was 150 days [IR: 60-365] with no statistically significant differences among the APs involved and the clinical entity (data not shown).
NPT-LASA was positive in 156 cases: 81 in NERD (77.14%) and in 75 cases confirmed as blended (68.18%) (Table 5). DPT to ASA was needed to establish the diagnosis in 246 CR patients (50.3%) as they had NPT-LASA negative and/or only one episode reported: 19 were NERD (18.09%), 37 NECD (75.51%), 166 NIUA (73.77%) and 24 blended (21.81%). In 87 CR cases (17.79%) the diagnosis was established by clinical history as they reported 3 or more unequivocal episodes induced by NSAIDs: 5 were NERD (4.76%), 12 NECD (24.48%), 59 NIUA (26.22%), and 11 blended (10%) (Table 5).
All SRs tolerated ASA in DPT. In 10 SNIDR cases (43.47%), patch test to the culprit was positive: 4 cases reporting contact eczema (3 induced by ketoprofen and 1 by dexketoprofen), 3 cases of fixed drug eruption (2 induced by naproxen and 1 by ibuprofen), 2 cases of MPE, and 1 case of AE induced by ketoprofen. In 125 SNIUAA (83.33) and 10 SNIDR (43.47%) patients the diagnosis was established by clinical history as they reported at least two unequivocal episodes induced by APs. However, in 28 SR cases (16.18%) DPT with the culprit was required as the patients reported only one episode induced by APs and patch tests were negative: 25 SNIUAA (16.66%) and 3 SNIDR (13.04%) (Table 5). No differences were found comparing the dose inducing the reaction and the positive response in DPT as well as the interval time between the last dose and the onset of both the reaction reported by patient and the one in a positive DPT, considering each AP and each the clinical entity (data not shown).