Diagnosing middle ear infection 

A middle ear infection (otitis media) can usually be diagnosed using an instrument called an otoscope.

An otoscope is a small handheld device with a magnifying glass and a light source at the end. Using an otoscope, a doctor can examine the ear to look for signs of fluid in the middle ear, which may indicate an infection.

Signs of fluid in the middle ear can include the ear drum:

  • bulging
  • being an unusual colour (usually red or yellow)
  • having a cloudy appearance

In some cases, a hole may have developed in the eardrum (perforated ear drum) and there may be fluid in the ear canal (the tube between the outer ear and eardrum).

Some otoscopes can also be used to blow a small puff of air into the ear to check for any blockages in the middle ear, which could be a sign of an infection. If the Eustachian tube (the tube that connects the throat and middle ear) is clear, the eardrum will move slightly. If it's blocked, the eardrum will remain still.

Further tests

Further tests are normally only required if treatment isn't working or complications develop. These tests will usually be carried out at your local ear, nose and throat (ENT) department.

Some of the tests that may be carried out are described below.


Tympanometry is a test that measures how the ear drum reacts to changes in air pressure.

During a tympanometry test, a probe is placed into your child's ear. The probe changes the air pressure at regular intervals while transmitting a sound into the ear. A measuring device is attached to the probe to record how the drum moves and how changes in air pressure affect this movement.

A healthy ear drum should move easily if there's a change in air pressure. If your child's ear drum moves slowly or not at all, it usually suggests there's fluid behind it.


Audiometry is a hearing test that uses a machine called an audiometer to produce sounds of different volume and frequency. This can help determine if your child has any hearing loss as a result of their condition.

During the test, your child listens through headphones and is asked if they can hear the sounds.


On the very rare occasions where there's a possibility the infection has spread out of the middle ear and into the surrounding area, a scan of the ear may be carried out. This may be either a:

A CT scan takes a series of X-rays and uses a computer to assemble the scans into a more detailed image, whereas an MRI scan uses strong magnetic fields and radio waves to produce images of the inside of the body.

Page last reviewed: 28/02/2016

Next review due: 28/02/2018