Hypersensitivity to Non-Steroidal Anti-Inflammatory Drugs on a pediatric Portuguese cohort.

Summary: Background. Non-steroidal anti-inflammatory drugs (NSAID)/analgesics (paracetamol) are among the most common causes of drug hypersensitivity reactions in children, with a reported prevalence of around 0.3% in the pediatric population. Paracetamol and ibuprofen are the most commonly reported culprits in the pediatric population. Our objective was to describe the allergy workup to NSAID/paracetamol of a pediatric population monitored in an allergy outpatient clinic. Methods. Retrospective observational study by consulting the medical records of patients evaluated in a pediatric outpatient clinic with history of NSAID/paracetamol, between January 2016 to August 2022. Results. A total of 43 patients have been evaluated for NSAID/paracetamol suspected allergy: 53.5% females, mean age of 9.8 ± 5.1 years, 47.7% atopic. The drugs reported as culprits were: ibuprofen (75.6%), paracetamol (17.8%), metamizole (4.4%) and naproxen (2.2%) and clinical manifestations were mainly urticaria/angioedema and maculopapular exanthema. Skin tests were performed in 7 patients: paracetamol (n = 5) and metamizole (n = 2), which were all negative. Fourty-six drug provocation tests were performed: 28 with the culprit drug and 18 with an alternative one; only 2 were positive (ibuprofen - culprit NSAID group): one immediate periorbital angioedema and one delayed lip edema with oropharyngeal tightness. Conclusions. The investigation of allergy to NSAID/paracetamol in children remains a challenge. In our population, ibuprofen was the most common NSAID reported. There were only 2 (4.3%) mild reactions on DPT. We could allow the use of the culprit NSAID/analgesic in 11 patients and an alternative one in 9 patients. This study highlights the importance of DPT in children for a correct diagnosis of NSAID hypersensitivity and selection of an alternative drug.