Anaphylaxis in a Tertiary Care Center: Clinical characteristics, management gaps, and opportunities for improving patient care

Background: Anaphylaxis is a severe, potentially life-threatening allergic reaction with increasing global incidence. Real-world data on clinical characteristics and management in Thailand remain limited. Objective: This study aimed to evaluate the causes, clinical manifestations, management, outcomes, and follow-up of anaphylaxis in pediatric and adult patients and also identify opportunities for improvement. Methods: This retrospective descriptive study was conducted at Panyananthaphikkhu Chonprathan Medical Center from January 2015 to December 2020. Patients diagnosed with anaphylaxis according to the World Allergy Organization 2020 criteria were included. Demographics, triggers, clinical features, treatment, and outcomes were analyzed. Subgroup analyses assessed factors associated with hospital admission and length of stay (LOS). Results: A total of 386 anaphylaxis episodes from 364 patients were included, with an incidence of 80.26 per 100,000 visits. The mean age was 30.5 ± 19.2 years, with 78.2% adults. Food was the most common trigger (69.7%), particularly seafood, followed by drug-induced reactions (14%). Adrenaline was administered in 97.2% of cases; however, the mean time to administration was 24.5 minutes. Hospital admission occurred in 70.5% of cases, with a mean LOS of 1.1 ± 2.4 days, and 9.8% experienced recurrent symptoms. Adjunctive H2-antihistamine therapy was not associated with improved outcomes; admission rates were higher in patients receiving H2 blockers, while LOS was similar between groups. The proper dose of adrenaline was lower than expected, especially in pediatric groups (85.7%). Moreover, the overall rate of adrenaline prefilled prescriptions was solely 30.2%. Conclusion: Anaphylaxis occurred predominantly in adults, with food and drug exposure as major triggers. Dosing in children and delays in adrenaline administration and prescribing prefilled adrenaline remain a concern. These findings support guideline-based management and careful use of adjunctive therapies.