Supplementary Material for: Clinical Characteristics, Management, and Natural History of Chronic Inducible Urticaria in a Pediatric Cohort

<b><i>Background:</i></b> Some forms of chronic urticaria (CU) can be specifically attributed to a response to a definite trigger, referred to as chronic inducible urticaria (CIndU). We aimed to assess the demographics, clinical characteristics, comorbidities, natural history, and management of pediatric patients with CIndU. <b><i>Methods:</i></b> Over a 6-year period, children presenting to the allergy clinic at the Montreal Children’s Hospital (MCH) with CIndU were prospectively recruited. CU was defined as the presence of wheals and/or angioedema, occurring for at least 6 weeks. A standardized diagnostic test was used to establish the presence of a specific form of urticaria. Resolution was defined as the absence of hives for 1 year without treatment. <b><i>Results:</i></b> Sixty-four patients presented with CIndU, of which 51.6% were male, with a median age of 12.5 (interquartile range 7.3, 15.9) years. Cold CU and cholinergic CU were the most common subtypes (60.3 and 41.3%, respectively). Basophil counts were undetectable in 48.4% of the cases, and C-reactive protein levels were elevated in 7.8% of patients. Of all cases, 71.4% were controlled with second-generation antihistamines. The resolution rate was of 45.3% (95% confidence interval 33.1–57.5%), based on per-protocol population within the 6-year course of the study. Resolution was more likely in patients who presented with well-controlled urticaria control test scores and elevated CD63 counts and in those suffering from thyroid comorbidity. <b><i>Conclusion:</i></b> The natural history of CIndU resolution in pediatric patients was relatively low and was associated with elevated CD63 levels, as well as thyroid comorbidity.

**背景：** 部分慢性荨麻疹（chronic urticaria, CU）可明确归因于特定触发因素诱导的免疫应答，此类亚型被称为慢性诱导性荨麻疹（chronic inducible urticaria, CIndU）。本研究旨在评估儿童慢性诱导性荨麻疹患者的人口学特征、临床特点、合并症、自然病程及诊疗管理方案。**方法：** 本研究周期为6年，前瞻性招募了就诊于蒙特利尔儿童医院（Montreal Children’s Hospital, MCH）变态反应门诊的慢性诱导性荨麻疹儿童患者。本研究将慢性荨麻疹定义为风团和/或血管性水肿持续发作至少6周，采用标准化诊断试验明确患者所患荨麻疹的具体亚型。病情缓解定义为停药后1年无荨麻疹发作。**结果：** 本研究共纳入64例慢性诱导性荨麻疹患儿，其中男性占比51.6%，中位年龄为12.5岁（四分位间距7.3~15.9岁）。冷接触性荨麻疹与胆碱能性荨麻疹为最常见的亚型（占比分别为60.3%与41.3%）。48.4%的患者嗜碱性粒细胞计数无法检出，7.8%的患者C反应蛋白水平升高。71.4%的患者经第二代抗组胺药治疗后病情得到有效控制。基于研究6年随访期内的符合方案集人群，病情缓解率为45.3%（95%置信区间：33.1%~57.5%）。基线时荨麻疹控制测试评分控制良好、CD63计数升高以及合并甲状腺疾病的患者，更易实现病情缓解。**结论：** 儿童慢性诱导性荨麻疹的自然缓解率相对较低，且病情缓解与CD63水平升高及合并甲状腺疾病显著相关。