Biphasic systemic anaphylaxis: an inpatient and outpatient study

Area of Science:

• Allergy and Immunology
• Clinical Medicine
• Pharmacology

Background:

• Anaphylaxis is a severe allergic reaction that can be life-threatening.
• Biphasic anaphylaxis involves a recurrence of symptoms after an initial improvement.
• Understanding the incidence of biphasic reactions is crucial for patient management and monitoring.

Purpose of the Study:

• To determine the incidence of systemic biphasic anaphylactic reactions in both outpatient and inpatient settings.
• To characterize the clinical presentation and outcomes of biphasic anaphylaxis.

Main Methods:

• Retrospective data collection from 1988-1991 for outpatient anaphylactic reactions (n=44).
• Retrospective data collection from 1986-1992 for inpatient anaphylaxis admissions (n=59).
• Analysis of reaction patterns, including biphasic recurrence, and clinical manifestations.

Main Results:

• Only 5% (2/44) of outpatient anaphylactic reactions exhibited a biphasic pattern.
• 7% (4/59) of inpatients with systemic anaphylaxis experienced a biphasic reaction without re-exposure.
• Cutaneous manifestations were most common in outpatient reactions (57%).

Conclusions:

• Systemic biphasic anaphylactic reactions are infrequent in both outpatient and inpatient settings.
• Most anaphylaxis cases, whether in clinic or hospital, resolve without recurrence.
• Further research may be warranted to identify predictors of biphasic reactions.