Mastoiditis is a serious infection of the mastoid, the hard, prominent bone just behind and under the ear. It is rare and can be life threatening without treatment.

Symptoms of mastoiditis include swelling behind the ear, pus from the ear, throbbing pain, and difficulty hearing.

Usually, the cause is an untreated or antibiotic-resistant ear infection. This can spread to surrounding structures, including the mastoid.

Without effective antibiotic treatment, a bacterial infection can continue spreading throughout the bones of the skull and may travel through the blood to organs, including the brain.

Middle ear infections are often the cause of mastoiditis. These infections are most common in babies under 2 years of age.

Below, learn more about mastoiditis, including how doctors diagnose and treat it.

Mastoiditis symptoms may begin after symptoms of an ear infection seem to have resolved. Or, it may seem as though an ear infection has gotten worse.

If a person with a bacterial ear infection develops new symptoms, even while they are taking antibiotics, the doctor may check for mastoiditis.

Symptoms include:

  • intense, throbbing pain in or around the ear
  • pus or other fluids coming from the ear
  • a fever or chills
  • swelling behind or under the ear
  • redness behind the ear
  • a bad smell coming from the ear
  • the ear appearing to stick out more or be pushed forward
  • hearing problems, such as ringing in the ears
  • pain that might seem out of proportion

Here are some signs of mastoiditis in very young children:

  • mood changes
  • frequent crying
  • hitting the side of their head
  • pulling on their ears

In some people, the swelling that mastoiditis causes gets better, then worse. It is important not to assume that an infection is healing when the symptoms improve slightly.

Without treatment, mastoiditis can cause blood clots or develop into sepsis, a blood infection that can be life threatening.

Anyone with mastoiditis or an ear infection and confusion, a high fever, significant weakness, or swelling around their head needs emergency medical care.

Ear infections, and particularly middle ear infections, are the most common cause of mastoiditis.

The bacteria responsible can spread without effective treatment. This may happen, for example, if a person stops the course of treatment before it is complete. It may also happen if the bacteria are resistant to the prescribed antibiotics.

Less often, an abnormal growth of skin cells in the middle ear, called a cholesteatoma, can cause a blockage that allows bacteria to multiply and leads to mastoiditis.

Cholesteatomas can also cause ear polyps that may result in further obstruction.

A doctor may be able to diagnose mastoiditis by considering the symptoms, including the appearance of the swelling. Blood work or a CT scan of the ear can help rule out other health conditions.


Antibiotics can usually treat mastoiditis. Most people need to receive the treatment through an IV, which typically requires hospitalization.

If the first round of treatment does not work, the doctor may take a culture of the infection to determine the type of bacteria involved. They can then recommend a different course of antibiotics.


The first-line approach to surgery for mastoiditis is often a myringotomy. This involves making a hole in the eardrum, and draining fluid. In children, this procedure may involve placing tubes into the eardrum.

The person also needs either oral or IV antibiotics.

If there is a complication such as a blood clot or an abscess, a swollen mass of infected fluid, the person may need a mastoidectomy.

This operation involves removing the infected part of the mastoid. If there is an abscess, it may need draining.

Preventing ear infections

The best way to prevent mastoiditis is to receive effective treatment for any ear infections.

If a doctor prescribes antibiotics, it is crucial to take the entire course of treatment as instructed, even if the symptoms go away during the treatment. Taking only a partial dose of antibiotics makes it easier for the infection to return.

A person should not take any older antibiotics left over from an earlier illness. Taking the right antibiotics for each infection is critical.

To reduce the risk of developing an ear infection, make sure to wash the hands regularly and effectively, and avoid contact with people who are unwell.

Anyone with a weakened immune system, which may be due to HIV, diabetes, or certain treatments, should see a doctor immediately about any signs of an infection.

To diagnose mastoiditis, a doctor needs to perform an examination and ask questions about the symptoms. They check for symptoms and signs such as a fever, pain, fluid draining from the ear, and discolored, swollen skin.

They also ask about risk factors, such as previous surgeries or diseases of the ear. In young children, mastoiditis may be more obvious and easier to diagnose.

Typically, the doctor needs further tests to confirm a diagnosis. These include:

Without prompt treatment, mastoiditis can cause:

Complications that affect the area of the skull that encloses the brain occur in 6–23% of mastoiditis cases. If this happens, the person may have neck stiffness, headaches, seizures, and a change in mental status.

Also, in some cases, a person can develop a blood clot in the brain.

With prompt, aggressive treatment, the outlook for mastoiditis is usually good.

A 2014 study followed 32 children under 16 years old who were receiving treatment for mastoiditis in a hospital. Most had a successful recovery, and 54% had required a mastoidectomy. Three of the children with weak immune systems developed mastoiditis again and needed further surgery.

Anyone with intense ear pain and swelling needs medical attention. Look out for any mastoiditis symptoms in children who have recently had an ear infection and have pain or swelling around that ear.

Ear infections can be a common childhood ailment, and they can cause serious complications, including mastoiditis. A healthcare professional can give advice and recommend effective treatment.

If the symptoms do not improve within a few days, return to the doctor or ask for a second opinion.

Below are answers to common questions about mastoiditis, a serious infection of the hard, prominent bone that sits behind and under each ear.

What is silent mastoiditis?

“Silent mastoiditis” can refer to a form of the condition in which antibiotic treatment relieves the obvious symptoms but does not resolve the inflammation of the middle ear.

It is similar to “masked” mastoiditis, which is more rare. This refers to mastoiditis developing without any notable clinical symptoms. Both of these forms can be difficult to identify and treat.

Can mastoiditis develop without an ear infection?

Mastoiditis typically stems from a middle ear infection. When it results from another cause, the doctor may refer to it as “incipient” mastoiditis. For example, an infection of the mastoid air cells may develop without resulting from an ear infection.

Can mastoiditis go away on its own?

In some cases, mastoiditis can erode the bone and drain away through the eardrum. Usually, however, it requires medical care. Call a doctor immediately about mastoiditis symptoms or symptoms of an ear infection that do not improve with treatment. Anyone with ear infection symptoms should receive medical attention within 24-48 hours.