Malignant otitis externa Health Article

Definition

Malignant otitis externa is a disorder involving inflammation and damage of the bones and cartilage at the base of the skull.

Alternative Names

Osteomyelitis of the skull; Otitis externa - malignant

Causes, incidence, and risk factors

Malignant otitis externa is caused by the spread of an outer ear infection (otitis externa, also called swimmer's ear). It is an uncommon complication of both acute swimmer's ear and chronic swimmer's ear.

Risks for this condition include:

• Chemotherapy
• Diabetes
• Weakened immune system

External otitis is often caused by difficult-to-treat bacteria such as pseudomonas. The infection spreads from the floor of the ear canal to the nearby tissues and into the bones at the base of the skull. The infection and inflammation may damage or destroy the bones. The infection may spread more and affect the cranial nerves, brain, or other parts of the body.

Symptoms

• Drainage from the ear - yellow, yellow-green, foul smelling, persistent
• Ear pain - felt deep inside the ear and may get worse when moving head
• Hearing loss
• Itching of the ear or ear canal
• Fever

Signs and tests

A doctor will look into your ear for signs of an outer ear infection (otitis externa). The head around and behind the ear may be tender to touch. A nervous system (neurological) examination may show that the cranial nerves are affected.

If there is any drainage, the doctor may send it to the lab for a culture. The purpose of the culture is to look for bacteria or fungi, usually the bacteria Pseudomonas.

To look for signs of a bone infection next to the ear canal, the following tests may be performed:

• CT scan of the head
• MRI scan of the head
• Radionuclide scan