Outcomes of allergy/immunology follow-up after an emergency department evaluation for anaphylaxis

Background: Anaphylaxis guidelines currently recommend referring patients with anaphylaxis seen in the emergency department (ED) to an allergist for follow up. Objective: The objective of our study was to evaluate outcomes of allergy/immunology follow-up after an ED visit for anaphylaxis. Methods: A retrospective health records review was conducted from April 2008 to August 2012. Charts were reviewed independently by 2 allergists to determine outcomes. Descriptive statistics with corresponding 95% CIs were calculated. Results: Among 573 patients seen in the ED who met anaphylaxis diagnostic criteria, 217 (38%) had a documented allergy/immunology follow-up. After allergy/immunology evaluation, 16 patients (7% [95% CI, 5%-12%]) had anaphylaxis ruled out. Among those with an unknown ED trigger (n= 74), 24 (32% [95% CI, 23%-44%]) had a trigger identified; and, among those who had a specific suspected ED trigger (n= 143), 9 (6% [95% CI, 3%-12%]) had a trigger identified in a category other than the one suspected in the ED, and 28 (20% [95% CI, 14%-27%]) had an unknown trigger. Thus, there were a total of 77 patients (35% [95% CI, 29%-42%]) who had an alteration in the diagnosis of anaphylaxis or trigger after allergy/immunology evaluation. Four patients (2% [95% CI, 0.7%-4.6%]) were diagnosed with a mast cell activation disorder, and 13 patients (6% [95% CI, 4%-10%]) underwent immunotherapy or desensitization. Conclusion: Overall, 35% of the patients with suspected anaphylaxis in the ED had an alteration in the diagnosis or suspected trigger after allergy/immunology evaluation. These results underscore the importance of allergy/immunology follow-up after an ED visit for anaphylaxis.