Prognostic implications of therapy for necrotizing external otitis.

Necrotizing external otitis is a slowly progressive infection of the ear canal and basal skull caused by Pseudomonas aeruginosa. Treatment with aminoglycoside and antipseudomonal penicillin antibiotics significantly reduces extension of infection, decreases the severity of the associated cranial nerve injury, and limits disease-related mortality. Combined antimicrobial and surgical treatment appears to be more efficacious than antibiotics alone when evaluated for comparable stages of the disease. However, invasive surgical procedures may promote the spread of infection, particularly in the absence of appropriate antibiotic therapy. A high index of suspicion for the syndrome should be aroused when external otitis is present for longer than two weeks, especially after local debridement and topical antibiotic treatment. Aggressive use of systemic antibiotic therapy in diabetic patients, who are at greatest risk, should reduce disease extension and lessen the need for multiple surgical procedures.