Merck Manual

Please confirm that you are not located inside the Russian Federation


Malignant External Otitis

(Skull Base Osteomyelitis; Necrotizing Otitis Externa)


Bradley W. Kesser

, MD, University of Virginia School of Medicine

Last full review/revision Sep 2020| Content last modified Sep 2020
Click here for the Professional Version
NOTE: This is the Consumer Version. DOCTORS: Click here for the Professional Version
Click here for the Professional Version

Malignant external otitis is infection of the external ear that has spread to the skull bone (temporal bone) containing the ear canal, the middle ear, and the inner ear.

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. Methicillin-resistant Staphylococcus aureus (MRSA) has also been identified as a cause. Despite the name, the infection is not cancerous (malignant).


People with malignant external otitis have severe ear pain (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 along the base of the skull.


  • Computed tomography (CT) scan

  • Culture of discharge

  • Biopsy

The diagnosis of malignant external otitis is based on 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 from the ear canal and examine it under a microscope (biopsy) to make sure that the symptoms are not caused by cancer.


  • Antibiotics

  • Sometimes hyperbaric oxygen therapy

  • Control of diabetes

  • Repeated cleanings of the ear canal

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 high doses of an antibiotic such as ciprofloxacin taken by mouth. Some people may be treated in a high-pressure oxygen chamber (hyperbaric oxygen therapy). People who have extensive bone disease may require antibiotic therapy for a longer period.

Meticulous control of diabetes is essential. If possible, doctors stop giving any drug that suppresses the immune system.

Although surgery usually is not necessary, repeated cleanings and removal of dead skin and inflammatory tissue (debridement) in the ear canal in the doctor's office are necessary until the infection goes away.

NOTE: This is the Consumer Version. DOCTORS: Click here for the Professional Version
Click here for the Professional Version
Others also read

Also of Interest


View All
The Sinuses
The Sinuses
3D Models
View All
3D Model