Acute mastoiditis (AM) is a relatively rare complication arising from acute otitis media, a common condition among children. The COVID-19 pandemic has significantly impacted AM cases. We noted a surge in pediatric AM cases in Germany after COVID-19 restrictions were lifted in 2022. This study assesses AM incidence and the clinical course in children before, during, and after the pandemic. The study also explores complication rates and microbial changes. Participants: We included children (0-18 yr) diagnosed with AM who underwent mastoidectomy at a tertiary-care university hospital from January 2012 to June 2023.Objectives: We aimed to evaluate AM incidence during pre-COVID, COVID, and post-COVID periods; assess complications; and analyze the microbial spectrum.Data Analysis: Incidence and complication rates were compared between periods, along with the microbial spectrum. Population: 75 children were included (median age, 3.3 yr).Incidence: Significant increases in AM cases occurred in the post-COVID period compared to pre-COVID and COVID periods. No significant difference was observed between pre-COVID and COVID periods.Complications: Complication rates increased notably in the post-COVID period compared to pre-COVID and COVID periods with respect to more sensitive imaging methods being used in the post-COVID period. No significant difference was observed between pre-COVID and COVID periods.Spectrum of Pathogens: No significant differences were found in pathogen distribution between periods. Streptococcus pyogenes and Streptococcus pneumoniae were common throughout. The study highlights a substantial rise in AM cases and complications after COVID-19 restrictions were lifted in Germany. This underscores the importance of monitoring infectious diseases and their complications during health crises. Additionally, the study highlights the importance of contrast-enhanced imaging. Further research is needed to explore the mechanisms behind this trend. The study reveals a significant increase in pediatric AM cases and complications following the COVID-19 pandemic in Germany. Adequate computed tomographic or magnetic resonance imaging, including contrast enhancement, is shown to be a very important parameter beside clinical symptoms in deciding for the right therapy. Thus, surgical treatment became more important. Continuous monitoring and adaptive healthcare strategies during health crises are vital for optimal patient care. Further research is warranted to understand the reasons behind these trends and to inform future pandemic preparedness efforts.