RT Journal Article SR Electronic T1 Predisposing factors of childhood Henoch-Schönlein purpura in Anhui province, China JF Journal of Investigative Medicine JO J Investig Med FD BMJ Publishing Group Ltd SP jim-2018-000906 DO 10.1136/jim-2018-000906 A1 Yao Xu A1 Jing Jing Wang A1 Fei Fei Liu A1 Yue Wu A1 Yang Fang Wu A1 Sama Samadli A1 Huang Huang Luo A1 Dong Dong Zhang A1 Peng Hu YR 2018 UL http://hw-f5-jim.highwire.org/content/early/2018/12/06/jim-2018-000906.abstract AB Henoch-Schönlein purpura (HSP) is a common autoimmune vasculitis in childhood. The detailed pathogenesis of HSP is still unclear, whereas several types of predisposing factors have been proved to be the initial step. The objectives of present study were to analyze the distribution of predisposing factors, association of the predisposing factors with clinical manifestations and HSP relapse/recurrence. 1200 children with HSP were recruited between January 2015 and December 2017. We reviewed their laboratory tests and medical histories associated with HSP onset. The annual incidence of HSP was 8.13–9.17 per 100 000 in Anhui province. HSP occurred more commonly in spring and winter than in summer with an obvious west-to-east gradient. Cutaneous purpura was the most prevalent manifestation (100%), followed by arthritis/arthralgias (43.67%), abdominal pain (40.17%) and renal involvement (18.17%). On admission, series of potential infections were identified in 611 patients (50.92%). The histories of allergy, injury, surgery, vaccination and tick bite were declared by 231 patients (19.25%), 15 patients (1.25%), 12 patients (1.00%), 4 patients (0.33%) and 3 patients (0.25%), respectively. However, predisposing factors could not be identified in 521 children with HSP (43.42%) yet. 123 cases (10.25%) relapsed or recurred more than one time; the mean number was 2.92, and the mean interval was 11.4 weeks. The infection is the most frequent predisposing factor regardless of clinical phenotypes and relapse/recurrence, whereas the clinical manifestations exhibit an obvious heterogenicity according to different predisposing factors.