An ear infection (otitis media) can usually be diagnosed using a tool known as a pneumatic otoscope.
A pneumatic otoscope is a small, hand-held device that has a magnifying glass and a light source at the end. It is used to study the inside of the ear.
An otoscope can detect certain signs that would indicate fluid in the middle ear, which in turn may indicate an infection.
These include the ear drum:
- being pulled inwards
- being an unusual colour
- having a cloudy appearance, and bubbles and fluid inside the ear
The otoscope can also be used to blow a small puff of air into the ear. If the Eustachian tube (a tube that passes between your throat and middle ear) is clear, the eardrum will move slightly. If it is blocked, the eardrum will remain still. The examination will also show whether the eardrum is perforated (has a hole in it).
Other tests
Other tests are usually only required if treatment is not working or complications develop.
These tests are described below.
Tympanometry
Tympanometry measures how the ear drum reacts to changes in air pressure. A healthy ear drum should move easily if there is a change in air pressure.
During a tympanometry test, a probe placed into ear changes the air pressure at regular intervals while transmitting a sound into the ear.
The probe measures how sound reflects back from the ear, and how changes in air pressure affect these measurements. If less sound is reflected back when the air pressure is high, it usually indicates an infection.
Tympanocentesis
Tympanocentesis involves draining fluid out of the middle ear using a small needle. The fluid can then be tested for bacteria or viruses that could be responsible for the infection.
CT scans
A computer tomography (CT) scan may be used if it is thought the infection may have spread out of the middle ear.
A CT scan takes a series of X-rays and uses a computer to assemble the scans into a more detailed, ‘3D’ image of the skull.
