What is Malignant Otitis Externa?

Complication of Swimmer's Ear

Ear Anatomy
Ear Anatomy. A.D.A.M

Malignant otitis externa (MEO) is a rare complication of swimmer's ear that occurs when an outer ear infection spreads to nearby tissue and bone. Despite the name, the term "malignant" does not mean you have cancer. The term "malignant" was originally used by the doctor who discovered MEO due to the serious nature of the disease and it's rapid progression.With the advent of antibiotics, outcomes are much better and the name is a bit misleading as to the severity of the disease.

The most common strain of bacteria responsible for malignant otitis externa is pseudomonas aeruginosa.

Risk Factors

Malignant otitis externa occurs when swimmer's ear spreads beyond the ear canal and cause a tissue or bone infection of the skull, including the temporal bone. Several factors could cause this to happen including:

  • untreated swimmer's ear
  • resistant bacteria
  • compromised immune system from chemotherapy, diabetes, or other conditions

Other significant risk factors for acquiring malignant otitis externa include:

  • living in a warm humid climate
  • elderly
  • male
  • diabetic

Once the infection spreads beyond the external ear canal it typically cause a bone infection at the base of the skull, specifically the temporal bone where it can cause osteomyelitis. Further progression can lead to damage of the cranial nerves and facial nerve paralysis.


Symptoms of malignant otitis externa will vary between individuals based on circumstances and the progression of the infection.

Symptoms may include:


Malignant otitis externa is best diagnosed by a physician who specializes in disorders of the ear, nose and throat called an otolaryngologist, although it can be diagnosed by physicians in other specialties.

Your doctor will consider your health history including any risk factors you may have as well as your symptoms. Your doctor will try to examine your ear with an otoscope, however this may be painful depending on the extent and progression of the infection. They will also examine your head for tenderness. Many tests can be used to confirm a diagnosis of malignant otitis externa, your doctor may order some of the following tests depending on their preference and your individual circumstances.

  • blood tests
  • culture of ear drainage
  • radiographic imaging to look for osteomyelitis (CT scan, MRI, etc...)
  • biopsy of the tissue in the external ear canal


A long course (months) of antibiotics is usually necessary since bone infections are particularly hard to cure. Your doctor should wait until a culture of ear drainage can confirm the type of bacteria causing your infection. Cultures will also give your doctor information on which antibiotics will best treat your infection.

You will need to be monitored during this time and continue antibiotics until imaging procedures no longer show inflammation.

In severe cases surgery may be required to remove damaged bone.

Other things to be aware of:

  • Hyperbaric oxygen therapy is sometimes used in conjunction with antibiotic therapy to facilitate healing of damaged tissues.
  • If you have diabetes, you will need to maintain tight control of their blood sugar since elevated blood sugar levels aid the growth of bacteria.


Medline Plus. Malignant otitis externa. Accessed: January 29, 2014 from http://www.nlm.nih.gov/medlineplus/ency/article/000672.htm

Medscape. Malignant Otitis Externa. Accessed: January 29, 2014 from http://emedicine.medscape.com/article/845525-overview

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