Avoidance of nonsteroidal anti-inflammatory drugs after negative provocation tests in urticaria/angioedema reactions: Real-world experience.

Drug provocation tests (DPTs) are the gold standard in diagnosing nonsteroidal anti-inflammatory drug (NSAID) hypersensitivity; however, only few data about follow-up of patients with negative DPTs are actually available. The aim of this study was to assess patients' behavior in taking NSAIDs again and to evaluate NSAID tolerability after negative allergological workup. This is a follow-up study involving patients evaluated for history of cutaneous reactions (urticaria and or angioedema) after NSAID intake and with negative DPTs with the suspected NSAID. Patients were asked during a phone interview about the intake of NSAIDs, tolerance, or reasons of avoidance. The negative predictive value (NPV) of NSAIDs DPTs was calculated. One hundred eleven of 142 patients were successfully contacted; 46/111 (41.44%) took the same NSAID previously tested with two adverse reactions reported (4.34%). Fifty-three of 111 (47.74%) patients did not take the same NSAID, but 34 of them took at least another strong cyclooxygenase (COX) 1 inhibitor, with 1 adverse reaction (2.94%) and 19 of them took only weak COX-1 inhibitors. Twelve of 111 patients (10.8%) did not take any NSAID. Reasons for drug avoidance were mainly fear of reactions (70.8%) and no need (29.2%). NPV, overall, was 96.97% (95% confidence interval, 91-99%). Although NSAID hypersensitivity diagnosis was ruled out by oral provocation test, the majority of patients with a history of urticaria/angioedema avoided the intake of the tested NSAIDs for fear of new reactions, particularly when strong COX-1 inhibitor NSAIDs were involved. The high NPV value of DPT resulting from this study should reassure NSAID intake.

Provocation tests with the offending nonsteroidal anti-inflammatory drugs in patients with urticaria/angioedema reactions.

The provocation test (PT) with the suspected drug represents the gold standard in the diagnosis of non-IgE hypersensitivity reactions to nonsteroidal anti-inflammatory drugs (NSAIDs). Nevertheless, there is no consensus regarding the clinical management of suspected NSAID-sensitive patients. This study assessed if a PT with the suspected drug is a reliable and safe proceeding to confirm NSAID hypersensitivity in patients with a clinical history of urticaria/angioedema (Urt/AE). It also analyzed different patient characteristics (such as gender, age, atopy, dermographism, time interval between the last drug reaction, and number of previous NSAID reactions) in relation to PT positivity. One hundred fifty-nine patients with Urt/AE apparently related to assumption of one or more NSAIDs underwent PT with the suspected drugs. Moreover, to distinguish single/multiple NSAID reactivity in patients who did not tolerate the offending NSAID, another strong cyclooxygenase-1 inhibitor PT was performed. PT was negative in 142/159 patients (89.31%), ruling out a diagnosis of NSAIDs hypersensitivity; 17/159 patients (10.69%) experienced a reaction of Urt/AE during the PT: 8 patients were diagnosed as single reactors to NSAIDs and 4 as multiple reactors to NSAIDs. Those with a history of multiple NSAID reactions and male patients were both more likely to have a positive PT. Our results suggest that in all patients with history of NSAID cutaneous reactions, the NSAID hypersensitivity should be confirmed by an oral PT and that the diagnostic proceeding can safely start with the offending NSAID.