Mastoiditis is an infection of the mastoid bone of the skull. The mastoid is located just behind the outer ear.

Causes, incidence, and risk factors
Mastoiditis is usually caused by a middle ear infection (acute otitis media). The infection may spread from the ear to the mastoid bone of the skull. The mastoid bone fills with infected materials and its honeycomb-like structure may deteriorate.

Mastoiditis usually affects children. Before antibiotics, mastoiditis was one of the leading causes of death in children. Now it is a relatively uncommon and much less dangerous condition.


  • Drainage from the ear
  • Ear pain or discomfort especially in the bone behind the ear.
  • Fever, may be high or suddenly increase
  • Headache
  • Hearing loss
  • Redness of the ear or behind the ear
  • Swelling behind ear, may cause ear to stick out

Signs and tests
An examination of the head may reveal signs of mastoiditis. The following tests may show an abnormality of the mastoid bone:

  • CTscan of the ear
  • Head CT scan
  • Skull x-ray (this study is rarely used these days for diagnosis of mastoiditis)

A culture of drainage from the ear may show bacteria.

Mastoiditis may be difficult to treat because medications may not reach deep enough into the mastoid bone. It may require repeated or long-term treatment. The infection is treated with antibiotics by injection, then antibiotics by mouth.

Surgery to remove part of the infected bone and drain the mastoid cavity (mastoidectomy) may be needed if antibiotic therapy is not successful. Surgery to drain the middle ear through the eardrum (myringotomy or ‘tubes’) may be needed to treat the middle ear infection.

Expectations (prognosis)
Mastoiditis is curable with treatment. However, it may be hard to treat and may come back.


  • Destruction of the mastoid bone
  • Dizziness or vertigo (link to corresponding rachael’s website)
  • Epidural abscess
  • Facial paralysis
  • Meningitis
  • Partial or complete hearing loss
  • Spread of infection to the brain or throughout the body

Calling your health care provider
Call your health care provider if you have symptoms of mastoiditis.

Call for an appointment with your health care provider if:

  • You have an ear infection that does not respond to treatment or is followed by new symptoms
  • Your symptoms do not respond to treatment

Promptly and completely treating ear infections reduces the risk of mastoiditis.