Lee Sangil, Bellolio M Fernanda, Hess Erik P, Erwin Patricia, Murad Mohammad Hassan, Campbell Ronna L
Department of Emergency Medicine, Mayo Clinic Health System, Mankato, Minn.
Department of Emergency Medicine, Mayo Clinic, Rochester, Minn.
J Allergy Clin Immunol Pract. 2015 May-Jun;3(3):408-16.e1-2. doi: 10.1016/j.jaip.2014.12.010. Epub 2015 Feb 11.
A biphasic reaction is a potentially life-threatening recurrence of symptoms after initial resolution of anaphylaxis without re-exposure to the trigger. The infrequent nature of these reactions has made them difficult to study and predict.
The aim of this study was to evaluate the time of onset and predictors of biphasic anaphylactic reactions.
Original research studies that described biphasic reactions in case series or cohort studies were included. Studies that did not describe biphasic reactions and case series with less than 2 biphasic reactions were excluded. Data sources included MEDLINE, EMBASE, Web of Science, and Scopus from inception to January 2014 and bibliographies of included articles. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated for dichotomous variables. Inconsistency among studies was assessed with the I(2) statistic.
Twenty-seven observational studies that enrolled 4114 patients with anaphylaxis and 192 patients with biphasic reactions were included. The median time of symptom onset was 11 (range 0.2 to 72.0) hours. Food as the inciting trigger was associated with decreased risk (pooled OR 0.62, 95% CI: 0.4 to 0.94, I(2) = 0%) and an unknown inciting trigger with increased risk (pooled OR 1.72, 95% CI: 1.0 to 2.95, I(2) = 61%). Initial presentation with hypotension (pooled OR 2.18, 95% CI: 1.14 to 4.15, I(2) = 79%) was also associated with the development of a biphasic reaction.
Biphasic anaphylatic reactions were less likely among patients with food as an inciting trigger. Patients who present with hypotension or have an unknown inciting trigger may be at increased risk of a biphasic reaction. Clinicians should tailor observation periods for patients individually based on clinical characteristics.
双相反应是过敏反应最初症状缓解后，在未再次接触诱发因素的情况下症状潜在危及生命的复发。这些反应并不常见，因此难以进行研究和预测。
本研究旨在评估双相过敏反应的发作时间及预测因素。
纳入在病例系列或队列研究中描述双相反应的原始研究。未描述双相反应的研究以及双相反应少于2例的病例系列被排除。数据来源包括自数据库建立至2014年1月的MEDLINE、EMBASE、科学引文索引和Scopus以及纳入文章的参考文献。对二分变量计算合并比值比（OR）及95%置信区间（CI）。用I²统计量评估研究间的不一致性。
纳入了27项观察性研究，共4114例过敏反应患者和192例双相反应患者。症状发作的中位时间为11（范围0.2至72.0）小时。食物作为诱发因素与风险降低相关（合并OR 0.62，95%CI：0.4至0.94，I² = 0%），而未知诱发因素与风险增加相关（合并OR 1.72，95%CI：1.0至2.95，I² = 61%）。最初表现为低血压（合并OR 2.18，95%CI：1.14至4.15，I² = 79%）也与双相反应的发生相关。
以食物为诱发因素的患者发生双相过敏反应的可能性较小。出现低血压或诱发因素不明的患者发生双相反应的风险可能增加。临床医生应根据临床特征为患者个体化调整观察期。
