Rationale There is limited data regarding treatment and management of anaphylaxis due to unknown causes (AUC). This study aims to assess the socio-demographics, clinical characteristics and management of pediatric AUC cases across Canada.
Methods Data on 204 pediatric AUC cases were prospectively collected between 2011 and 2017 in emergency rooms at 5 centres across Canada (Montreal Children’s Hospital, Sacré-Coeur Hospital, Sainte-Justine Hospital, Janeway Children’s Hospital and BC Children’s Hospital) as part of the Cross-Canada Anaphylaxis Registry (C-CARE). Severe cases were defined as ones that manifested as cyanosis, hypoxia (saturation \u3c92%), respiratory arrest, hypotension, dysrhythmia, confusion or loss of consciousness. A primary analysis was done using multivariate logistic regression to identify factors associated with epinephrine treatment.
Results Among 204 cases of AUC, 54.5% were males, and the median age was 9.1 years (IQR: 5.1, 14.4). 18.2% (95%CI 13.3%, 24.4%) had asthma, and 43.3% (95%CI 36.5%, 50.5%) had a known food allergy. 37.7% (95%CI 30.8%, 45.0%) of cases were severe. Epinephrine was not administered in 27.1% (95%CI 21.2%, 33.8%) of cases. Epinephrine auto-injector was prescribed to 79.6% (95%CI 73.2%, 84.8%) of cases and 75.4% (95%CI 68.9%, 81.1%) were referred to an allergist. Anaphylactic reactions occurring at home were more likely to be managed without epinephrine (adjusted OR for age, sex, and presence of asthma: 2.4 (95%CI 1.1, 4.7).
Conclusions Our findings highlight the need to increase awareness of appropriate management of AUC with epinephrine followed by consultation with an allergist. It is possible that cases of AUC occurring outside the home have greater accessibility to epinephrine