Format

Send to

Choose Destination
J Allergy Clin Immunol Pract. 2014 May-Jun;2(3):281-7. doi: 10.1016/j.jaip.2014.01.012. Epub 2014 Apr 2.

Predictors of biphasic reactions in the emergency department for patients with anaphylaxis.

Author information

1
Department of Emergency Medicine, Mayo Clinic, Rochester, Minn. Electronic address: Lee.Sangil@mayo.edu.
2
Department of Emergency Medicine, Mayo Clinic, Rochester, Minn.

Abstract

BACKGROUND:

A biphasic reaction is the recurrence of anaphylaxis symptoms within 72 hours of the initial anaphylactic event, without re-exposure to the trigger. Biphasic reactions are uncommon and unpredictable, and risk factors for biphasic reactions are poorly understood.

OBJECTIVE:

To identify predictors of biphasic anaphylactic reactions in patients with anaphylaxis in the emergency department (ED).

METHODS:

Patients of all ages who presented to the ED and met diagnostic criteria for anaphylaxis from April 2008 to January 2013 at an academic medical center with 73,000 annual patient visits were consecutively included. We collected data on patient characteristics, suspected triggers, signs and symptoms, ED management, and disposition. Univariate analyses were performed to estimate the association between potential predictor variables and biphasic reactions. We report associations as odds ratios (OR) and corresponding 95% CIs.

RESULTS:

Among 541 patients with anaphylaxis, median age was 34.6 years (interquartile range, 18-52 years), and 320 (59%) were female patients. Twenty-one patients (4%) had biphasic reactions. Two pediatric patients, ages of 5 years old and 16 years old, developed a biphasic reaction. The median time between the resolution of initial symptoms and onset of the biphasic reaction was 7 hours (range, 1-72 hours). Biphasic reactions were associated with a history of prior anaphylaxis (OR 2.6 [95% CI, 1.1-6.4]; P = .029), unknown precipitant (OR 2.6 [95% CI, 1.1-6.2]; P = .03), symptoms of diarrhea (OR 4.5 [95% CI, 1.4-14.0]; P = .024), and wheezing (OR 2.6 [95% CI, 1.4-8.9]; P = .029).

CONCLUSIONS:

Patients with a history of prior anaphylaxis, an unknown precipitant, or who present with symptoms of diarrhea or wheezing may be at increased risk for a biphasic reaction.

KEYWORDS:

Anaphylaxis; Biphasic reactions; Emergency department; Risk factors

PMID:
24811018
DOI:
10.1016/j.jaip.2014.01.012
[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center