Background The sting challenge test (SCT) is regarded as the most reliable method for assessing the effectiveness of venom immunotherapy (VIT). However, its predictive value in patients undergoing VIT is still unclear. This study aims to evaluate the predictive value of the SCT. Methods A multicenter retrospective observational study was conducted on patients receiving VIT who underwent SCT. The study gathered data on patient demographics, diagnosis, immunotherapy details, outcomes of the SCT and their comparison to subsequent field sting (FS) results. Results A total of 261 patients were included, and 372 SCT were recorded. The majority of the patients (75.1%) were men. A diagnosis of mastocytosis was confirmed in 7.7%. The final diagnoses were allergy to Apis mellifera (48.7%), Polistes dominula (36.8%), Vespula spp. (2.7%) and Polistes dominula plus Vespula spp. (10,7%). Sting challenge tests were performed with Apis in 61.6% of the overall tests, Polistes in 34.1% and Vespula in 4.3%. The majority (95.7%) of the SCT were negative. Regarding FS, 146 patients (56.2%) experienced 306 FS of which 95.1% were negative. Among these 146 patients, 137 had a negative SCT, and 130 of these also had a subsequent negative FS, resulting in a 94.9% of negative predictive value (NPV) of the test. Of the patients who experienced FS, 9 had a positive SCT and only 3 of them had a positive FS, resulting in a positive predictive value of 33,3%. Conclusions SCT is a safe procedure, and its high NPV emphasizes the usefulness of this test in assessing the effectiveness of VIT.

Clinical letter

Background : Non-steroidal anti-inflammatory drugs (NSAIDs) are one of the main causes of hypersensitivity to drugs in the paediatric population. Studies about the natural history of cross-intolerance reactions to NSAIDs are scarce. The aim of this study was to assess cross intolerance to NSAIDs over time in the paediatric population. Methods : Retrospective study in patients under 18 years old diagnosed with cross intolerance to NSAIDs by oral challenge test between 1999 and 2019. These patients were prospectively re-assessed in 2021-2022 by challenge with acetylsalicylic acid (ASA). Patient characteristics and potential factors that might have helped them develop tolerance to NSAIDs were analysed. Results : Between 1999 and 2019, 46 patients were diagnosed with cross intolerance to NSAIDs; of these, 19 were re-assessed at a second visit after a mean of 116 months from initial diagnosis. The NSAID most involved in reactions was ibuprofen. At Visit 2, it was observed that 15 (78.9%) patients tolerated ASA and other NSAIDs. Patients with atopy and who initially presented with asthma were more likely to maintain their diagnosis of cross intolerance to NSAIDs ( p=0.001 and p=0.035, respectively). On the contrary, most patients with initial angioedema developed tolerance over time ( p=0.035). Conclusion : Patients with cross intolerance to NSAIDs may develop tolerance to them over time. This tolerance might be determined both by the presence of atopy and the initial history of the patient.