Association between biphasic reactions and the systems of symptoms and treatment in patients with anaphylaxis hospitalized from the emergency department

AIM: Anaphylaxis is a severe, life‐threatening, generated or systemic reaction, and biphasic reaction could occur in some cases. We investigated the clinical course of anaphylaxis in our hospital and studied the relationship between biphasic reactions and the symptoms and treatments for predicting the onset of biphasic reactions. METHODS: We retrospectively reviewed the medical records of 120 patients with anaphylaxis who were admitted to our hospital from the emergency department during April 2008–October 2015. RESULTS: The incidence of biphasic reactions of anaphylaxis in our hospital was 10.8% (13 patients) without significant difference when compared with that in previous reports. Regarding the development of biphasic reactions, symptoms, the number of systems of symptoms and severity of the initial reaction, and treatment with adrenaline and corticosteroid were not clearly related with biphasic reaction. Use of adrenaline in the initial treatment was approximately 60%. Of the 13 biphasic reactions, 11 (84.5%) were as equal/mild as the original symptoms. CONCLUSION: This study could not show the factors predicting the onset of biphasic reactions. Further prospective and nationwide studies are required to research biphasic reactions.