We report the case of a pediatric patient in whom a spinal congenital dermal sinus was detected after the onset of anaerobic bacterial meningitis. The patient was a 4-month-old boy. He had a recurrent fever for 2 weeks before admission. On admission, he presented with a convulsive status and a bulging anterior fontanel. The previously consulted physician had made a diagnosis of bacterial meningitis. Spinal fluid cultures tested positive for Peptoniphilus asaccharolyticus. Magnetic resonance imaging (MRI) showed a spinal subdural abscess and cranial subdural hydrops；therefore, the patient was transported to our hospital for surgical treatment. A sacral dimple was noted on his lower back, and an MRI showed a spinal congenital dermal sinus. Antimicrobial therapy, cranial subdural aspiration, dermal sinus excision, and drainage were performed. He was discharged on the 60th hospital day. When pathogens such as Staphylococcus aureus or Escherichia coli,Proteus sp. or anaerobic bacteria invade through a dermal sinus, it can result in meningitis. Involvement of a dermal sinus should be suspected when meningitis is caused by these pathogens or when recurrent meningitis occurs.
