Allergic emergencies in the prehospital setting: a 5-year retrospective study

Background. Patients with severe allergic conditions often request support from the prehospital emergency services given the rapid, unexpected and po-tentially life-threatening nature of the reactions, such as anaphylaxis. Studies regarding prehospital incidents for allergic conditions are scarce. This study aimed to characterize prehospital medical requesting assistance due to suspected hypersensitivity reactions (HSR). Methods. Retrospective study of allergic-re-lated requesting assistances between 2017 and 2022 of a Portuguese emergency dispatch center ‒ Emergency and Resuscitation Medical Vehicle (VMER) ‒ in Coimbra University Hospital. Demographic and clinical variables were analyzed, including clinical manifestations, anaphylaxis severity grading, therapeutic interventions, and post-incident allergic work-up. Regarding anaphylactic events, three diagnosis timings were compared: on-site, hospital emergency department and investigator-diagnosis based on data reviewed. Results. Out of 12,689 VMER requesting assistances, 210 (1.7%) were classified as suspected HSR reactions. After on-site medical evaluation, 127 (60.5%) cases maintained the HSR classification (median age 53 years; 56% males) and the main diag-noses included HSR to Hymenoptera venom (29.9%), food allergy (29.1%), and pharmaceutical drugs (25.5%). Anaphylaxis was assumed on-site in 44 (34.7%) cases, in the hospital emergency department in 53 cases (41.7%) and by investigators in 76 (59.8%) cases. Regarding management, epinephrine was administered on-site in 50 cases (39.4%). Conclusions. The main reason for prehospital requesting assistance was HSR to Hymenoptera venom. A high proportion of incidents met the criteria for anaphylaxis and despite the inher-ent difficulties of the prehospital setting, many of the on-site diagnoses agreed with the criteria. Regarding management, epinephrine was underused in this setting. After pre-hospital events, a proper referral to a specialized consultation is crucial for a full diagnostic work-up and disease management.