Objective  To summarize the clinical characteristics and explore the risk factors of Kawasaki disease(KD) with deep neck space involvement(DNSI).

  Methods  This study was a case-control study. We reviewed KD complicated with DNSI patients in Department of Rheumatology and Immunology of Shenzhen Children's Hospital from January 2018 to December 2020 as DNSI group. Meanwhile, children with KD withoutDNSI during this period were selected by systematic sampling at a ratio of 1∶7 as control group. The clinical characteristics were analyzed by Chi-square test and the Mann-Whitney test and risk factors of KD complicated with DNSI were analyzed by Logistic regression.

  Results  A total of 38 children in the DNSI group who met the inclusion and exclusion criteria and 288 children in the control group were selected. In the DNSI group, 38 children (100%) had fever and cervical lymph node enlargement, and the cervical lymph node enlargement occurred within 5 days of onset; 30 patients (78.9%) had cervical lymph node pain and 25 patients suffered (65.8%) limited movement of neck. Compared with the control group, the clinical data of children in the DNSI group showed a variety of significant changes. In terms of clinical characteristics, the age of onset in the DNSI group was older, the hospital stay was longer and the proportions of cervical lymphadenopathy, cervical lymph node pain, limited neck movement and upper airway obstruction were all higher (all P < 0.05); in terms of laboratory tests, the neutrophil count and its percentage, C-reactive protein (CRP), ferritin (FER), total bile acid, total bilirubin, direct bilirubin, and globulin levels all increased, while platelet and lymphocyte counts and their percentages all decreased(all P < 0.05); in terms of coronary artery damage and treatment effect, the Kobayashi score, Sano score and the proportion of hormone therapy in the DNSI group all increased (all P < 0.05). Multivariate Logistic regression analysis showed that neck lymph node pain (OR=5.523, 95% CI: 1.443-21.141, P=0.013), limited cervical movement (OR=3.947, 95% CI: 1.044-14.928, P=0.043), higher CRP (OR=1.016, 95% CI: 1.002-1.030, P=0.024) and higher FER(OR=1.004, 95% CI: 1.001-1.006, P=0.002) were independent risk factors for KD combined with DNSI.

  Conclusions  Most children with KD complicated with DNSI have clinical symptoms such as cervical lymph node enlargement, cervical lymph node pain, and limited cervical movement, and hematology shows that there is a high-intensity inflammatory response. For KD children with neck pain and limited cervical movement as the main clinical manifestations, accompanied by elevated serum CRP and FER, we should be alert to the possibility of DNSI.