Cervical abscess caused by methicillin-susceptible Staphylococcus aureus in an infant infected with SARS-CoV-2: Diagnostic dilemma

A new inflammatory disease has emerged in children after the COVID-19 disease and has been named multisystem inflammatory syndrome in children (MIS-C). We report a case of cervical abscess in an infant with COVID-19 who was first considered to have MIS-C due to persistent fever, high inflammatory markers. A 10-month-old boy was admitted to the emergency department due to a 3-day fever and cervical lymphadenopathy. SARS-CoV-2 RNA was detected by a real-time reverse transcriptase-polymerase chain reaction in the nasopharyngeal swab specimen of the patient. Regarding initial clinical and laboratory findings, the patient was diagnosed to have MIS-C and bacterial co-infection. Clindamycin and ceftriaxone treatments were initiated for bacterial co-infection. Despite treatment, his fever persisted and acute phase reactants compatible with MIS-C were elevated and intravenous immunoglobulin (IVIG) was administered. After IVIG treatment, his fever persisted and the patient developed local inflammatory signs including erythema, tenderness, fluctuation developed. Cervical ultrasonography and magnetic resonance imaging demonstrated the findings compatible with the cervical abscess. Drainage of the cervical abscess was performed by an otolaryngologist. Methicillin-susceptible Staphylococcus aureus was isolated from the abscess culture. After abscess drainage, fever and acute phase reactants declined. His nasopharyngeal swab was negative for SARS-CoV-2 on the 7th day. He was discharged on the 21st day of hospitalization with full recovery. To the best of our knowledge, no cases of COVID-19 with cervical abscess caused by Staphylococcus aureus in children had been reported previously. Bacterial co-infection should be kept in mind in children infected with SARS-CoV-2 and showing MIS-C findings.