Observation Periods and Biphasic Reaction Risk Factors in Pediatric Emergency Anaphylaxis Cases

November 14, 2025 updated by: Aykut Çağlar, MD, Aydin Adnan Menderes University

Evaluation of Observation Periods and Biphasic Reaction Risk Factors in Pediatric Anaphylaxis Cases in the Pediatric Emergency Department: A Retrospective Study

This study reviews the medical records of children who presented to the pediatric emergency department of Adnan Menderes University Hospital with a diagnosis of anaphylaxis between January 2014 and December 2024. The aim is to determine how long children were observed in the emergency department, how often biphasic reactions (a second wave of symptoms) occurred, and which risk factors (such as delayed adrenaline use or asthma) may increase this risk. The results will help improve the care of children with anaphylaxis and guide recommendations for safe observation times.

Study Overview

Status

Completed

Conditions

Detailed Description

Anaphylaxis is a severe, potentially life-threatening systemic hypersensitivity reaction with rapid onset. Its incidence in children has been rising worldwide. Although international recommendations emphasize the importance of post-reaction monitoring, the optimal observation period in pediatric patients remains uncertain, largely due to the risk of biphasic reactions, defined as recurrence of symptoms after initial resolution within 1-72 hours.

This retrospective observational study was conducted in the Pediatric Emergency Department of Adnan Menderes University Hospital. All patients younger than 18 years who presented with anaphylaxis between January 1, 2014, and December 31, 2024, were included. Diagnosis was based on the World Allergy Organization (WAO) 2020 criteria. Data were obtained from electronic medical records and emergency department charts.

Collected variables included demographics (age, sex), season of presentation, suspected triggers (food, drug, insect sting, exercise, idiopathic), clinical manifestations (cutaneous, respiratory, cardiovascular, gastrointestinal, neurological), comorbidities (such as asthma), acute treatments (epinephrine administration, time to first dose, number of doses, corticosteroids, antihistamines, fluid therapy), observation duration, need for hospital admission, and occurrence of biphasic reactions.

The primary objective is to determine the incidence and timing of biphasic reactions. Secondary objectives are to assess the average observation period in the emergency department, the frequency of hospital admission, and risk factors associated with biphasic reactions, including delayed epinephrine administration and history of asthma. Statistical analysis will include descriptive methods, group comparisons, and logistic regression to identify independent predictors of biphasic reactions.

This study is expected to contribute real-world data on pediatric anaphylaxis and inform clinical practice regarding safe observation times. Results will be compared with existing evidence and may support improvements in pediatric emergency protocols for anaphylaxis management.

Study Type

Observational

Enrollment (Actual)

67

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Child

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

Children and adolescents (<18 years) who presented to the Pediatric Emergency Department of Adnan Menderes University Hospital between January 1, 2014, and December 31, 2024, with a diagnosis of anaphylaxis.

Description

Inclusion Criteria:

Age <18 years

  • Diagnosis of anaphylaxis according to World Allergy Organization (WAO) 2020 criteria
  • Complete clinical data available in medical records

Exclusion Criteria:

  • Incomplete or missing clinical data
  • Cases not meeting WAO 2020 anaphylaxis definition
  • Patients presenting with isolated urticaria or localized allergic reactions only

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
Pediatric Anaphylaxis Cohort
Children under 18 years of age who presented to the Pediatric Emergency Department of Adnan Menderes University Hospital between January 2014 and December 2024 with a diagnosis of anaphylaxis, defined according to WAO 2020 criteria. All patients meeting eligibility criteria were included retrospectively from medical records.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Incidence of Biphasic Reactions
Time Frame: Within 72 hours of the initial anaphylaxis episode
he proportion of pediatric patients who developed a biphasic reaction, defined as recurrence of anaphylaxis symptoms after complete resolution of the initial episode, within 1-72 hours.
Within 72 hours of the initial anaphylaxis episode

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Mean Observation Period in the Pediatric Emergency Department
Time Frame: During index visit (hours)
Average length of observation (in hours) in the pediatric emergency department following initial anaphylaxis management.
During index visit (hours)
Risk Factors Associated with Biphasic Reactions
Time Frame: During index visit and follow-up within 72 hours
Identification of independent predictors for biphasic reactions (e.g., history of asthma, delayed epinephrine administration, initial clinical severity, need for multiple epinephrine doses).
During index visit and follow-up within 72 hours

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Aydin Adnan Menderes University

Investigators

  • Principal Investigator: Aykut Çağlar, Aydın Adnan Menderes University Hospital, Department of Pediatric Emergency Care

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

May 1, 2014

Primary Completion (Actual)

November 1, 2024

Study Completion (Actual)

October 1, 2025

Study Registration Dates

First Submitted

November 14, 2025

First Submitted That Met QC Criteria

November 14, 2025

First Posted (Actual)

November 17, 2025

Study Record Updates

Last Update Posted (Actual)

November 17, 2025

Last Update Submitted That Met QC Criteria

November 14, 2025

Last Verified

November 1, 2025

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • ADUPEDANAPH

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

We do not plan to share individual participant data. Summary results will be available in published articles.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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