Malignant external otitis is infection of the external ear that has spread to involve the skull bone containing part of the ear canal, the middle ear, and the inner ear (temporal bone).
Malignant external otitis occurs mainly in people with a weakened immune system and in older people with diabetes. Infection of the external ear, usually caused by the bacteria Pseudomonas, spreads into the temporal bone, causing severe, life-threatening infection. Despite the name, the infection is not cancerous (malignant). Other names include necrotizing otitis externa and skull base osteomyelitis.
People have severe earache (often worse at night), a foul-smelling discharge from the ear, pus and debris in the ear canal, and usually decreased hearing. In severe cases, paralysis of nerves in the face and head may occur as the infection spreads.
The diagnosis is based on computed tomography (CT) scan results. Doctors also do a culture (a sample of the discharge is grown in a laboratory to identify the microorganisms). Often doctors need to take a small piece of tissue (biopsy) from the ear canal to make sure that the symptoms are not caused by cancer.
Typically, malignant external otitis is treated with a 6-week course of antibiotics given by vein. However, people with a mild infection may be treated with a high-dose antibiotic such as ciprofloxacin taken by mouth. People who have extensive bone disease may require antibiotic therapy for a longer period. Meticulous control of diabetes is essential. Although surgery usually is not necessary, repeated cleanings and debridement of the ear canal in the doctor's office are necessary until the infection goes away.
Last full review/revision February 2013 by Bradley W. Kesser, MD