Low Incidence of Biphasic Allergic Reactions in Patients Admitted to Intensive Care after Anaphylaxis

Abstract

Editor’s Perspective What We Already Know about This Topic What This Article Tells Us That Is New Background Biphasic allergic reactions—recurrence of allergy symptoms after a symptom-free period—are reported to occur in 1 to 23% of allergic reactions. Patients admitted to an intensive care unit after anaphylaxis potentially have more severe reactions and a higher risk of biphasic allergic reactions. The purpose of this study was to examine incidence, triggers, symptoms, and treatment of biphasic allergic reactions, in patients admitted to an intensive care unit. Methods Records of patients admitted to intensive care units with anaphylaxis from 2011 to 2014 were reviewed. Only patients with a reaction fulfilling internationally accepted criteria for anaphylaxis were included. Potential biphasic allergic reactions, defined as renewed allergy symptoms 1 to 72 h after initial symptoms had resolved, without further exposure to the trigger, were identified. Results A total of 83 cases of anaphylaxis were identified, and the most frequent triggers were medications (58 of 83 [70%]). Skin symptoms occurred in 69 (83%) cases, and circulatory and respiratory symptoms in 48 (58%) and 45 (54%) cases, respectively. In total, 82 (99%), 80 (96%), and 66 (80%) were treated with antihistamines, corticosteroids, and epinephrine, respectively. Only 10 patients presented with one or more relevant symptoms after the initial allergic reaction. Of these, three were possible, and one was a probable biphasic allergic reaction, giving a total incidence of 4 of 83 (4.8% [95% CI, 1.6 to 12.5]) or 1 of 83 (1.2% [95% CI, 0.1 to 7.46]), respectively. All cases were mild, presenting with skin symptoms only, occurring on average 14 h after initial reactions. Conclusions The authors observed a low incidence of biphasic reactions in patients admitted to an intensive care unit after anaphylaxis, at a rate equivalent to that reported in other patient groups.

Medicolegal Implications of Biphasic Anaphylaxis

“…), absence of witnesses and rescuers, lack of observation protocols and reliable diagnostic laboratory tests, and nonspecific macroscopic and microscopic findings at autopsy. [1][2][3][4][5][6][7][8][9][19][20][21][22][23]32,38,[47][48][49]75,79,80 Forensic pathologists and coroners may be required by the courts to evaluate not only the survivors of a biphasic anaphylactic episode (in the event of medical malpractice claims) but also fatalities where it is necessary to ascertain:…”

“…New rapid-response analytical techniques, faster than common enzyme-linked immunosorbent assay and radioallergosorbent test procedures, are also needed especially, but not only for use in emergency departments. [2][3][4][6][7][8][24][25][26][27][30][31][32]62,[69][70][71][72][73][74][77][78][79][80][88][89][90]99 Lastly, further research should be undertaken to explore other potential anaphylaxis biomarkers and to improve current laboratory procedures both for clinical practice (such as developing innovative analyte sampling protocols and rapid-response analytical technologies for emergency applications) and for postmortem investigations (by identifying more stable, meaningful, and reliable analytes for testing). 20,75,79,80,99,102…”

“…27 -People with a previous history of anaphylactic IgE-mediated reactions, whether uniphasic or biphasic. [1][2][3][4][5][6][7][8][9]24,38 -Oral administration of the offending antigen. [2][3][4]38,39 -Unknown antigen responsible for the primary reaction.…”

“…This is of critical importance in terms of the relevant clinical and medicolegal implications. [1][2][3][4][5][6][7][8][9]23,31,38,45,61,71,72 Simons et al 69,[73][74][75] maintain that 6 to 12 hours is appropriate for patients with respiratory symptoms, a period which can be extended up to 12 to 24 hours in cases of hemodynamic disturbance requesting significant doses of epinephrine during the first reaction.…”

“…[1][2][3][4][5] The 3 main time courses of anaphylactic events are (1) uniphasic or monophasic when the patient has a single reaction, (2) protracted when the patient's anaphylactic symptoms take a long time to resolve despite relevant treatment, and (3) biphasic when the patient has a recurrence of symptoms after a symptomfree period. 6 Biphasic, or rebound, anaphylaxis occurs when a patient is apparently successfully treated for a primary anaphylactic IgE-mediated reaction, but subsequently develops a second, or "biphasic," reaction, in the absence of any further exposure to the trigger antigen. [1][2][3][4][5]7,8 An anaphylactic reaction, whether uniphasic, protracted, or biphasic, is regarded as a sudden and potentially fatal pathological IgE-mediated event.…”