Symptomatology and Management of Adult Anaphylaxis according to Trigger: A Cross-Sectional Study.

Introduction: Anaphylaxis is an acute life-threatening allergy, most commonly provoked by food, venom, or drugs. There is limited data regarding differences in symptomatology between anaphylaxis provoked by different triggers. This study aimed to assess sociodemographic characteristics, clinical symptoms, and management of anaphylaxis, according to triggers in adults.

Methods: We conducted a cross-sectional study recruiting adult patients with anaphylactic reactions across 8 emergency departments (EDs) and 1 electronic medical service (EMS) in Canada. Univariate and multivariate regression models were used to evaluate symptoms involving all patients with the outcome of drug-induced anaphylaxis (DIA), venom-induced anaphylaxis (VIA), peanut-induced anaphylaxis (PIA), shellfish-induced anaphylaxis, tree-nut induced anaphylaxis (TIA) and nut-induced anaphylaxis (NIA). We assessed comorbidities associated with severe reactions, stratified by triggers listed above. Additionally, we evaluated the association of each trigger with treatment through regression models involving all patients with medications used as outcome and anaphylaxis triggers used as independent variables.

Results: From April 2011 to November 2023, 1,135 adults presenting with anaphylaxis to EDs were recruited. The median age was 35.5 (interquartile range 25.3-51.1). Most of the patients presented with FIA (50.3%). Regarding symptomatology, hypotension was more likely associated with DIA (aOR = 1.20, 95% CI = 1.11-1.30, p < 0.01). When adjusted for age at reaction and male sex, alcohol was more likely associated (aOR = 1.51, 95% CI = 1.04-2.19, p = 0.035) with NIA. Regarding management, TIA was more likely associated with inpatient epinephrine (aOR = 2.05, 95% CI = 1.16-3.64, p = 0.014). DIA was less likely associated with outpatient antihistamine (aOR = 0.68, 95% CI = 0.48-0.89, p < 0.01) whereas TIA was more likely associated with outpatient antihistamine (aOR = 1.81, 95% CI = 1.03-3.19, p = 0.040).

Conclusion: Our study underscores associations between specific triggers, clinical manifestations and managements, such as the potential link between TIA and throat tightness and hypotension and VIA. Identifying such associations can aid with the prompt diagnosis of anaphylaxis in patients presenting to the ED, leading to swifter treatment initiation and improving overall outcomes.