Anaphylaxis severity grade, during oral food challenges, assessed by five different classifications.

Background: While the definition of anaphylaxis is clear, its grade of severity remains a subject of debate. The objective of this study was to evaluate the possible discrepancies in the severity scoring system for anaphylaxis in patients with a positive food challenge (OFC), differentiating anaphylactic and non-anaphylactic reactions, using the WHO for the 11th version of the International Classification of Diseases (ICD-11) as the main reference.

Methods: We conducted a retrospective observational study at the University Hospital of Montpellier, France, including patients with a positive food OFC between 2018 and 2022. We classified the severity of each reaction based on 5 different classifications. We also compared patients presenting an anaphylactic versus a non-anaphylactic reaction during the OFC in terms of symptoms and therapeutic approach.

Results: 235 patients presented a positive OFC between January 2018 and December 2022: 143 (60.9%) suffered from anaphylaxis, according to the ICD-11 classification. When comparing the different classifications, a complete concordance was recorded in 8 patients (5.6%) only. All classifications showed a good sensitivity (99.3%-100%), but different specificity (67.4%-93.5%), and discrepancies between them were shown in most patients. Respiratory and gastrointestinal symptoms were significantly more frequent in the anaphylaxis group. Adrenaline was injected in only 47.6% of patients suffering from anaphylaxis, even in a specialized setting.

Conclusion: Our work highlights the need to refine the different scoring systems and, even better, to disseminate unified diagnostic criteria, such as the ICD-11 ones, to avoid the underdiagnosis of anaphylactic reactions and ensure appropriate management for all allergic patients.