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The rarest of all ear infections, mastoiditis is a bacterial infection that affects the mastoid, a delicate bone behind the ear. Its structure is similar to that of a honeycomb, helping to maintain air space in the middle ear. When the mastoid becomes infected or inflamed, the porous bone begins to break down, causing visible swelling.

The infection normally occurs as a result of a persistent middle ear infection, and can spread outside of the mastoid bone, causing multiple complications if not dealt with quickly. The infection is most common in children, although adults can also be affected too. If you or your child has recently suffered from a middle ear infection, take heed of your doctor's advice and recovery recommendations to minimise the risks of developing mastoiditis.


Mastoiditis symptoms can often be very similar to other ear infections, but with an increased visibility of evidence. Warning signs include the following:

  • Fever
  • Irritability
  • Lethargy
  • Swelling behind the ear
  • Redness and tenderness of the ear
  • Ear discharge
  • A middle ear infection that seemingly hasn't gone away


Mastoiditis normally develops after a middle ear infection, where bacteria from the middle ear travels into the air cells of the mastoid bone. However, it can also be caused by cholesteatoma, an abnormal collection of skin cells in the middle ear that can cause extensive inflammation and spread of infection to the mastoid.


If you suspect that you might have developed mastoiditis, you should seek the advice of a doctor as soon as possible. They will invite you for an initial ear examination, where they will look inside the ear to evaluate your ear's function and check for inflammation. If they suspect infection, they may recommend other tests to confirm diagnosis, including x-rays, blood tests and swabbed ear-fluid cultures. If the infection is thought to be severe, you may also be sent for a CT or MRI scan.

In rare cases, mastoiditis can develop into meningitis when the lining of the brain becomes inflamed.


Once your diagnosis has been made, you are likely to be prescribed oral antibiotics, eardrops or regular ear cleanings. For cases of acute mastoiditis, treatment may take place in a hospital, where antibiotics will be administered by an IV drip.

Surgery is also an option, removing the mastoid bone completely or draining the ear. Ear draining is known as a myringotomy, and works by making a small hole in your eardrum to release pressure and allow fluid to escape. An operation to remove the mastoid bone is known as a cortical mastoidectomy, and will only take place if the infection is severe. If a severely infected bone is not removed, there is a risk of developing blood clots or brain abscesses, which can be life-threatening.

After surgery, patients will be expected to stay in hospital for a few days, and will not be allowed to get the operated ear wet for at least a week after hospital release. Swimming is allowed after four to six weeks, depending on how well the surgery has healed. Your GP will be able to advise on recovery milestones at check-up meetings.

If you suspect you have mastoiditis, contact your GP as soon as possible. For more information about other forms of ear infections, visit our overview, otitis externa, otitis media or labyrinthitis pages.