Objective：To investigate the clinical features of periodic fever syndrome（PFS） in children and to improve the understand－ing of the disease. Methods：A retrospective analysis was performed on the clinical data，laboratory examinations，and genetic diagnoses of 17 children with PFS who attended the University of Hongkong-Shenzhen Hospital from February 2014 to June 2018. Results：There were 11 and 6 children who were diagnosed with periodic fever，aphthous stomatitis，pharyngitis，and adenitis syndrome（PFA－PA） and familial Mediterranean fever（FMF），respectively. The median duration of fever episode，the highest temperature during each episode，and the median interval between episodes were 4.5 days，40 ℃，and 4 weeks，respectively，for PFAPA，and 3.25 days，40 ℃，and 4 weeks，respectively，for FMF. Among the patients with PFAPA，11（100%） had pharyngitis，7（63.6%） had cervical lymphadenitis，7（63.6%） had an oral ulcer，3（27.3%） had abdominal pain，and 1（9.1%） had a rash. Among the patients with FMF，2（33.3%） had abdominal pain，2（33.3%） had cervical lymphadenitis，2（33.3%） had an oral ulcer，and 2 （33.3%） had pharyngitis. Laboratory examinations revealed elevated levels of white blood cells（WBC），C-reactive protein（CRP），and erythrocyte sedimentation rate（ESR） but normal procalci－tonin（PCT） and negative results of microbiological and autoantibody tests in all the patients with PFS during fever episode. Gene de－tection revealed 1 site mutation in the MEFV gene in 4 out of 11 patients with PFAPA and 2-3 site mutations in the MEFV gene in all the 6 patients with FMF. Conclusion：PFS should be considered in patients suffering from periodic fever along with symptoms such as pharyngitis and cervical lymphadenitis accompanied by elevated CRP and ESR as revealed by laboratory examinations. Meanwhile，this study suggests that PCT can assist the differential diagnosis between PFS and bacterial infection.
