Medically Reviewed By William C. Lloyd III, MD, FACS
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What is mastoiditis?

Mastoiditis is a bacterial infection of the mastoid bone or mastoid process. This bone sits within the skull and is located directly behind the ear. It contains pockets called air cells that drain the middle ear. Because the mastoid bone connects to the middle ear, mastoiditis is most commonly a complication of an ear infection. It occurs when the infection spreads from the ear into the air cells. It is possible to get mastoiditis without ear infection, but this is very rare.

Middle ear infections occur much more frequently in children than adults. This makes children more likely to get mastoiditis. However, mastoiditis is not a common condition today thanks to antibiotics and vaccines. Before antibiotics, about 20% of ear infections resulted in mastoiditis. And mastoiditis frequently caused serious complications and even death in children who developed it.

Pneumococcus (Streptococcus pneumoniae) are the most common bacteria that cause mastoiditis. Along with antibiotics, the pneumococcal conjugate vaccine has helped decrease the incidence of mastoiditis.

Mastoiditis symptoms usually accompany ear infection symptoms. This includes ear pain, ear drainage, fever, hearing problems, and headache. Sometimes, swelling of the mastoid bone is visible behind the ear. It can progress to the point that the cleft or crease behind the ear disappears. This can cause the ear to stick out instead of lying flat.

Mastoiditis treatment can be challenging. It generally requires IV (intravenous) antibiotics followed by antibiotics you take by mouth. But it may return and become a chronic problem. Should this occur, it is necessary to surgically drain the mastoid bone by removing part of it.

Complications from mastoiditis can be quite serious. Contact your doctor promptly if your child has an ear infection that isn’t responding to treatment or if new symptoms develop despite treatments. Seek immediate medical care if you notice facial asymmetry or changes in the position of the ear.

What are the symptoms of mastoiditis?

In most cases, mastoiditis develops as a complication of a bacterial middle ear infection—otitis media. Otitis media symptoms include ear pain, ringing in the ear, fever, hearing problems, and possibly balance problems. In young toddlers, it can be hard for them to communicate what they are feeling. Clues can include ear tugging, not eating normally, and unusual crying or irritability.

Common symptoms of mastoiditis

Mastoiditis causes the following symptoms:

  • Headache
  • Hearing problems
  • Redness behind the ear
  • Swelling behind the ear, which can fill the crease behind the ear causing it to protrude or look asymmetrical compared to the other ear

Serious complications can develop from mastoiditis. Seek immediate medical care (call 911) if you, or your child, have symptoms that could indicate mastoiditis. Contact your doctor or seek prompt medical care for an ear infection that isn’t getting better with treatment or if you notice new symptoms.

What causes mastoiditis?

While mastoiditis is not a common condition, it almost always occurs as a complication of a bacterial middle ear infection. Most of the infections that lead to mastoiditis are due to pneumococcal bacteria. Other bacteria that can cause mastoiditis include Group A streptococci, Staphylococcus aureus, Streptococcus pyogenes, and Haemophilus influenzae.

The infection spreads from the middle ear to the mastoid bone that sits just behind the ear. It settles in pockets in the bone called air cells. It can be difficult for antibiotics to reach these honeycomb-like structures deep in the bone.

What are the risk factors for mastoiditis?

Children are at higher risk of mastoiditis than adults because they are more likely to get middle ear infections. Other risk factors for mastoiditis include:

  • Age less than two years
  • Immune suppression or being immunocompromised
  • Incomplete or abnormal formation of the air cells
  • Recurrent otitis media

Reducing your risk of mastoiditis

The best way to prevent mastoiditis is to seek prompt treatment for ear infections. Antibiotics can treat the infection and stop it from spreading to the mastoid bone. However, it’s important to take the full prescribed course of antibiotics. Stopping them before completing the course increases the risk of recurrence with a resistant strain of bacteria that does not respond to typical antibiotics for ear infections.

Completing your child’s pneumococcal vaccination schedule can also help prevent mastoiditis. The infant schedule involves four doses at two, four, six and 12 months.

How do doctors diagnose mastoiditis?

Mastoiditis is usually a clinical diagnosis. This means doctors use your medical history and physical exam to reach a diagnosis. If you have drainage from your ear, your doctor will likely send the fluid to a lab to see what kind of bacteria is growing. Sometimes, they take a sample of fluid through the eardrum. Doctors may also order a CT (computed tomography) scan or other imaging exam to gauge the extent of infection.

What are the treatments for mastoiditis?

Since mastoiditis is a bacterial infection, antibiotics are necessary to treat it. Usually, doctors start with IV antibiotics and transition to oral antibiotics for at least two weeks. It can be difficult for antibiotics to reach the deep tissues involved in mastoiditis. As a result, it can recur and become chronic. In this situation, doctors may recommend surgery to remove part of the mastoid bone and drain the infection. Surgery may also be necessary if an abscess forms in the bone.

Sometimes, doctors recommend surgery to address the middle ear infection, as well. It involves draining the middle ear through the eardrum. Ear tube placement may be part of treatment for some children. This helps the middle ear stay clear of fluid accumulation. The tubes usually fall out by themselves after several months.

What are the potential complications of mastoiditis?

Most of the time, doctors can cure mastoiditis with antibiotics or surgery. Before antibiotics, this was not the case and complications were common. Today, complications are far less likely to occur. Possible mastoiditis complications include:

  • Abscess in nearby tissues, including the brain
  • Facial paralysis due to nerve damage
  • Hearing loss in the affected ear, which can be partial or complete
  • Sepsis and spread of infection throughout the body

What does mastoiditis look like?

Signs of mastoiditis include swelling and redness behind the ear, as shown in the image below.

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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2021 Mar 11
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THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
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