Subperiosteal abscess developed from acute otitis media caused by Group A <i>Streptococcus</i> in a child with cochlear implant

Introduction Infections with Group A Streptococcus are currently increasing in number worldwide as a result of lifting of contact restrictions during the COVID-19 pandemic.Case presentation We report a case of temporal subperiosteal abscess that developed from severe acute otitis media in a child with cochlear implant. Myringotomy and drainage of the subperiosteal abscess were performed. Group A Streptococcus infection caused severe inflammation of the middle ear mucosa, resulting in rapid spread outside the temporal bone via the mastoid cavity, forming a subperiosteal abscess around the cochlear implant.Discussion Children apparently often develop temporal swelling caused by acute inflammation after cochlear implantation. Acute otitis media in patients with a cochlear implantation requires attention to both central nervous infections, such as meningitis, and inflammation outside the temporal bone. Drainage through myringotomy should be considered at an early stage in addition to sufficient antimicrobial therapy in order to prevent progression.