Necrotizing 'malignant' external otitis caused by Staphylococcus epidermidis

Necrotizing "malignant" external otitis is a life-threatening skull base infection that originates in the external auditory canal and is characterized by otalgia and purulent aural discharge with external auditory canal cellulitis and granulation. Necrotizing external otitis, seen almost exclusively in elderly diabetics, is almost always caused by Pseudomonas aeruginosa. To our knowledge, there have been only six nonpseudomonal cases reported to date. We describe a 70-year-old diabetic man with necrotizing external otitis caused by Staphylococcus epidermidis, confirmed by serial cultures. This case was characterized by otalgia, purulent otorrhea, preauricular swelling, bony external auditory canal erosion, and a conductive hearing loss. Despite prolonged intravenous antistaphylococcal antibiotic therapy and frequent local débridement, the patient's symptoms never completely resolved. As demonstrated by the treatment failure, S epidermidis necrotizing external otitis, may represent a more refractory form of this already virulent disease process. We believe this to be the first reported case of necrotizing external malignant otitis caused by S epidermidis.