OBJECTIVE: This study examined the clinical characteristics of MUMPP and the effects of various treatments on children with MUMPP during March 2023 to February 2024 in southern China. METHODS: We conducted a retrospective case-control study at a university-affiliated hospital in southern China. Patients were categorized based on their response to macrolide treatment into two groups: MUMPP and control group. The study included 549 pediatric patients. Of these, 297 were in the MUMPP group and 252 were in the control group. This categorization allowed us to compare clinical characteristics and laboratory indicators between the groups. The MUMPP group received one of the three treatments: combined antibiotics, additional steroids, or a switch to doxycycline. Subsequently, we analyzed differences in clinical outcomes, which included hospital stay, hospital cost, and recovery time. RESULTS: No significant differences were found in gender or pre-admission disease duration between the MUMPP and control group (P>
0.05). However, subjects in MUMPP group was older, had longer fever durations, extended hospital stays, higher medical costs, and elevated levels of C-reactive protein, lactate dehydrogenase, IL-6, and γ-IFN. All of which showed statistically significant differences (P<
0.05). Within the MUMPP group, patients switched to doxycycline had the shortest hospital stay and recovery time, significantly differing from those in other treatment groups (P<
0.05). CONCLUSION: Children in the MUMPP group exhibited higher inflammatory indicators than the control group. The early adaptation of treatment strategies, particularly the switch to doxycycline, is associated with improved clinical outcomes.