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


Mastoiditis is most often caused by a middle ear infection (acute otitis media). The infection may spread from the ear to the mastoid bone. The bone has a honeycomb-like structure that fills with infected material and may break down.

The condition is most common in children. Before antibiotics, mastoiditis was one of the leading causes of death in children. The condition does not occur very often today. It is also much less dangerous.


Exams and Tests

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

A culture of drainage from the ear may show bacteria.


Mastoiditis may be hard to treat because the medicine may not reach deeply into the bone. The condition sometimes requires repeated or long-term treatment. The infection is treated with antibiotic injections, followed by antibiotics taken by mouth.

Surgery to remove part of the bone and drain the mastoid (mastoidectomy) may be needed if antibiotic treatment does not work. Surgery to drain the middle ear through the eardrum (myringotomy) may be needed to treat the middle ear infection.

Outlook (Prognosis)

Mastoiditis can be cured. However, it may be hard to treat and may come back.

Possible Complications

When to Contact a Medical Professional

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

Also call 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


Prompt and thorough treatment of ear infections reduces the risk of mastoiditis.


Chole RA, Sudhoff HH. Chronic otitis media, mastoiditis, and petrositis. In: Flint PW, Haughey BH, Lund LJ, et al, eds.Cummings Otolaryngology: Head & Neck Surgery

Klein JO. Otitis externa, otitis media, and mastoiditis. In: Mandell GL, Bennett JE, Dolin R, eds.Principles and Practice of Infectious Diseases

O'Handley JG, Tobin EJ, Shah AR. Otorhinolaryngology. In: Rakel RE, ed.Textbook of Family Medicine

Update Date 8/4/2014

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