Cotton bud in external ear canal causing necrotising otitis externa and subdural abscess

Abstract

Necrotising otitis externa (NOE) is an infection originating in the soft tissues of the external auditory canal (EAC) spreading to the surrounding bone and rarely causing intracranial complications. It is usually caused by Pseudomonas aeruginosa and has historically occurred in elderly patients with diabetes or immunodeficiency. EAC foreign body is a risk factor for otitis externa but has not been described in NOE. A healthy 31-year-old man presented with new-onset seizures and worsening left-sided otalgia and otorrhoea. Brain imaging revealed left temporal subdural abscesses superior to the petrous bone. A retained cotton bud was identified in the left EAC, along with osseocartilaginous junction and mastoid granulation tissue. The foreign body was removed; a cortical mastoidectomy performed and intravenous antibiotic administered. At 10 weeks, the patient remained well, with no neurological deficit and no residual ear symptoms, and CT demonstrated complete resolution of the intracranial abscesses.