Background: Allergy is witnessing major advances, in particular with the advent of biological therapies for treating allergic diseases. Given the novelty of these therapeutics, we aimed to explore by a worldwide survey, the prescription and the management of hypersensitivity reactions (HR) of biological agents (BA) in Allergy. Method: We built up an anonymous online questionnaire, sent out by mail and social media and circulated for 40 days. Results: 348 responses were from 59 countries, with a majority from Europe (62.6%). 97% of responders practiced allergy and 48.5%, exclusively so. Allergy was mentioned as a full specialty in 69.5 % of cases. 71% of responders confirmed the right of prescription of BA for allergists in their country and 78.4 % prescribed BA in their clinical practice. Europe included almost all the allergists who did not have the right of prescribing BA (95.5%), specifically France (91%). The most prescribed BA were Anti IgE (78.1%) and anti IL5 (43.9%). The most declared HR to BA were local reactions (74.1%) followed by anaphylaxis like symptoms (6.8%) and delayed exanthemas (5.1%). Desensitization was considered in 18.9% of cases. These HR were reported in 48.8% of cases. Conclusion: Although BA are now a pillar in the treatment of allergic diseases and allergists are familiar with management of HR associated with BA, their prescription is not authorized for allergists in all countries. BA showed to be generally safe but HR, which may be severe, could occur with a lack of consensus on the management.

The International Classification of Diseases (ICD) provides a common language for use worldwide as a diagnostic and classification tool for epidemiology, clinical purposes and health management. Since its first edition, the ICD has maintained a framework distributing conditions according to topography, with the result that some complex conditions, such as allergies and hypersensitivity disorders (A/H) including anaphylaxis, have been poorly represented. The change in hierarchy in ICD-11 permitted the construction of the pioneer section addressed to A/H, which may result in more accurate mortality and morbidity statistics, including more accurate accounting for mortality due to anaphylaxis, strengthen classification, terminology and definitions. The ICD-11 was presented and adopted by the 72nd World Health Assembly in May 2019 and the implementation is ongoing worldwide. We here present the outcomes from an online survey undertaken to reach out the allergy community worldwide in order to peer review the terminology, classification and definitions of A/H introduced into ICD-11 and to support their global implementation. Data are presented here for 406 respondents from 74 countries. All of the sub-sections of the new A/H section of the ICD-11 had been considered with good accuracy by the majority of respondents. We believe that, in addition to help during the implementation phase, all the comments provided will help to improve the A/H classification and to increase awareness by different disciplines of what actions are needed to ensure more accurate epidemiological data and better clinical management of A/H patients.