Health Library

Mastoiditis

Mastoid bone infection

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

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Causes

Mastoiditis is most often caused by a middle ear infection (acute otitis media). The infection may spread from the ear to the mastoid bone. This 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.

Symptoms

Symptoms include:

• Drainage from the ear
• Ear pain or discomfort
• Fever, may be high or suddenly increase
• Headache
• Hearing loss
• Redness of the ear or behind the ear
• Swelling behind the ear may cause ear to stick out or feel as if it is filled with fluid

Exams and Tests

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

• CT scan of the ear
• Head CT scan
• Head MRI scan

A culture of drainage from the ear may show bacteria.

Treatment

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

Complications may include:

• Destruction of the mastoid bone
• Dizziness or vertigo
• Epidural abscess
• Facial paralysis
• Meningitis
• Partial or complete hearing loss
• Spread of infection to the brain or throughout the body

When to Contact a Medical Professional

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

Also contact 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.
• You notice any facial asymmetry.

Prevention

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

Related Information

References

Player B. Otitis media. In: Kliegman RM, St. Geme JW, Blum NJ, et al, eds. Nelson Textbook of Pediatrics. 22nd ed. Philadelphia, PA: Elsevier; 2025:chap 680.

Tähtinen PA, Pelton SI. Otitis externa, otitis media, and mastoiditis. In: Blaser MJ, Cohen JI, Holland SM, et al, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 10th ed. Philadelphia, PA: Elsevier; 2026:chap 63.

Weinreich HM, Martin E, Santos F. Chronic otitis media, mastoiditis, and petrositis. In: Francis HW, Haughey BH, Hillel AT, et al, eds. Cummings Otolaryngology. 8th ed. Philadelphia, PA: Elsevier; 2026:chap 139.

Review Date: 4/29/2026  

Reviewed By: Ashutosh Kacker, MD, FACS, Professor of Clinical Otolaryngology, Weill Cornell Medical College, and Attending Otolaryngologist, New York-Presbyterian Hospital, New York, NY. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

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