Anaphylaxis: first clinical presentation, subsequent referral practise, and suspected elicitor-an observational study

Anaphylaxis is an allergic manifestation characterised by rapid onset and progression. Rapid treatment may be challenging in patients with atypical symptoms or no previous history of anaphylaxis. This study aimed to describe the clinical prehospital presentation of first-time anaphylactic patients. To help target educational initiatives, we sought to identify which groups of medical professionals are most likely to encounter first-time anaphylactic patients and investigated the referral pattern for suspected anaphylactic patients for specialised treatment. A retrospective register-based study from the Region of Southern Denmark. Patients referred to the Allergy Centre, Odense University Hospital, from 2019 to 2021 were included. The medical records were manually reviewed for first contact with the emergency departments or the emergency medical service. 444 patients with suspected anaphylaxis were referred. 226 patients had grade 3-5 systemic allergic reactions as classified by the World Allergy Organisation; 90% had cutaneous symptoms, 63% symptoms from the central nervous system, 42% gastrointestinal symptoms, 40% cardiovascular symptoms, 36% had upper-airway symptoms, and 36% had lower-airway symptoms. Patients treated prehospitally had a significantly more severe degree of anaphylaxis than patients only treated within the hospital. More than half of the patients with suspected anaphylaxis were referred to the Allergy Centre from the emergency departments. Patients with allergies progressing to severe anaphylaxis most often are treated prehospitally before transport to emergency departments. From the emergency departments, they are referred to the allergy centre. Education concerning the immediate treatment of severe anaphylaxis should primarily be targeted towards prehospital care providers.