Mastoiditis is a serious bacterial infection that affects the mastoid bone behind the ear.

It's usually more common in children, although adults can also sometimes be affected.

The mastoid bone has a honeycomb-like structure that contains air spaces called mastoid cells. The mastoid cells help maintain the air space in the middle ear.

Mastoiditis can develop if the mastoid cells become infected or inflamed, often as a result of a persistent middle ear infection (otitis media). This can cause the porous bone to break down.

Symptoms of mastoiditis

Mastoiditis typically causes:

redness, tenderness and pain behind the ear

swelling behind the ear that can cause it to stick out

discharge from the ear

a high temperature, irritability and tiredness


hearing loss in the affected ear

When to see your GP

Call your GP if you or your child:

has any symptoms of mastoiditis

has an ear infection that doesn't clear up with treatment or is followed by new symptoms

has been diagnosed with mastoiditis and treatment hasn't cleared it up

What causes mastoiditis?

Mastoiditis usually occurs following an untreated middle ear infection. Bacteria from the middle ear can spread to the inner ear, infecting the mastoid cells of the mastoid bone.

Cholesteatoma can also cause mastoiditis. This is an abnormal collection of skin cells inside the ear which may prevent the ear draining properly, leading to infection.

How mastoiditis is diagnosed

Your GP will examine the inside of the ear with an otoscope (a device with a light and magnifying glass) to check for signs of infection or cholesteatoma.

Most ear infections are middle ear infections. If your GP thinks you have mastoiditis as a complication of a middle ear infection, they'll refer you to an ear, nose and throat (ENT) specialist. They will carry out a further examination and tests – usually a blood test and an ear culture (where discharge from the ear is tested for a bacterial infection).

Some children may need to have a computerised tomography (CT scan), which uses X-rays and a computer to create detailed images of the inside of the skull.

How mastoiditis is treated

Mastoiditis is a serious infection and should be treated quickly. It's treated with antibiotics.

You may need to go to hospital so that you can be given antibiotics directly into a vein through a drip. In some cases, surgery may be needed to drain your middle ear (a myringotomy) or to remove part of the mastoid bone (mastoidectomy).

If you're admitted to hospital for treatment you'll need to stay in for a few days until the ENT specialists can be sure the infection is under control.

After surgery

If you've had surgery for mastoiditis, you'll probably need to take one or two weeks off work. Your doctor will advise you about this.

Take care not to get the affected ear wet. You should be able to wash your hair after about a week, providing you don't get water inside your ear.

You should be able to go swimming around four to six weeks after the operation, depending on how well your ear has healed. Your doctor should be able to advise you at your follow-up appointment.


With early antibiotic treatment, most people with mastoiditis recover quickly and have no complications. However, treatment isn't always easy and the infection may come back.

If the mastoid bone is severely infected and isn't removed, it can cause hearing loss and life-threatening health complications such as a blood clot, meningitis, or a brain abscess.