Selective hypersensitivity to a single nonsteroidal anti-inflammatory drug.

The aim of the study was to explore the frequency and the clinical and diagnostic characteristics of a single nonsteroidal anti-inflammatory drug-induced hypersensitivity (SNIUAA) subgroup.In the hospital information system we identified patients who performed the oral provocation test (OPT) with analgesics between 2004 and 2016. We divided patients into phenotype groups based on clinical history and OPT results.Altogether, 248 patients (44.3% of phenotyped patients) were diagnosed with SNIUAA. The most common offending drug in SNIUAA was diclofenac (52.4%), followed by pyrazolones (30.7%). In the group with selective diclofenac hypersensitivity, there was a larger percentage (40.0%) of patients with anaphylaxis. Compared to other phenotypes, significantly fewer patients had OPT performed with the suspected drug in SINUAA; however, in 69.4% of patients in this group, OPT with acetylsalicylic acid was performed.SNIUAA was the most common phenotype of nonsteroidal anti-inflammatory drug hypersensitivity in our cohort. Diclofenac was the most common cause of the hypersensitivity reaction and also the most common cause of anaphylactic reaction. In the group of patients with a positive history after taking diclofenac or pyrazolone, fewer OPTs with the suspected drug were performed, but more often OPT with aspirin to prove that hypersensitivity is selective.