Epidemiology and clinical predictors of biphasic reactions in children with anaphylaxis

Anaphylaxis—a 2020 practice parameter update, systematic review, and Grading of Recommendations, Assessment, Development and Evaluation (GRADE) analysis

“…35,36 Estimates of biphasic anaphylaxis vary from <1% to 20% of patients; however, the ability of antihistamines and glucocorticoids to affect this outcome is unclear. [37][38][39][40][41][42][43][44] Despite a lack of clear evidence supporting the role of antihistamines and glucocorticoids in anaphylaxis, these agents continue to be routinely used in anaphylaxis management. To evaluate the role for these second-line, supplemental therapies, the Joint Task Force on Practice Parameters (JTFPP) undertook a systematic review and Grading of Recommendations, Assessment, Development and Evaluation (GRADE) analysis of antihistamines and glucocorticoids in anaphylaxis.…”

“…[37][38][39] More contemporary studies of biphasic anaphylaxis utilizing the NIAID/FAAN diagnostic criteria or similar criteria for diagnosis of both the initial anaphylactic reaction and the biphasic reaction have demonstrated lower rates of biphasic reactions closer to 4% to 5% (range, 0.18%-14.7%). [40][41][42][43][44] No studies have systematically evaluated therapies for the second-phase reaction; however, therapy for the second phase is similar to that for the initial phase. 36 Optimal duration of extended observation following resolution of biphasic anaphylaxis is unknown.…”

Duration of Observation for Detecting a Biphasic Reaction in Anaphylaxis: A Meta-Analysis

“…This result, derived from the systematic review and meta-analysis, can serve as a rationale for the postanaphylactic observation time recommended in the current guidelines. However, the duration should be adjusted according to clinical factors such as the severity of the early-phase reaction [23], the early administration of epinephrine [18], and inciting trigger factors [5], as well as the institutional policy and resources. Given that the severity of the secondary reaction tended to be similar to or milder than the initial anaphylaxis symptom, increasing the observation period to obtain additional NPV increases seems not to lead to any further gain in a practical sense.…”

Prevalence of biphasic response in anaphylaxis due to purposeful administration of allergenic food

“…This explanation is supported by the fact that a delay in presentation to the ED was a predictor of biphasic reactions in the current report and in other studies. 1,7 In addition, reports of patients with anaphylaxis presenting to the ED in the United States found that repeated doses of epinephrine were associated with an increased likelihood of an overnight admission and were an indicator anaphylaxis severity. 8,9 Second, during the OFC and OIT dosing, the amount of ingested food is known and only slightly exceeds the threshold of tolerance or a dose that was tolerated previously.…”

“…One may translate these findings into every child with an anaphylactic-type reaction needs prolonged observation of at least 6 hours in mild cases. 1 The authors did not discuss the reactions after observed exposure to allergenic foods, such as those exposures during oral food challenges (OFCs) or oral immunotherapy (OIT) dosing. We are concerned that adopting a recommendation for an extended period of observation may deter allergists from performing an OFC, an important and underused procedure.…”