Your doctor can usually diagnose an ear infection or another condition based on the symptoms you describe and an exam. The doctor will likely use a lighted instrument (an otoscope) to look at the ears, throat and nasal passage. He or she will also likely listen to your child breathe with a stethoscope.
An instrument called a pneumatic otoscope is often the only specialized tool a doctor needs to make a diagnosis of an ear infection. This instrument enables the doctor to look in the ear and judge whether there is fluid behind the eardrum. With the pneumatic otoscope, the doctor gently puffs air against the eardrum. Normally, this puff of air would cause the eardrum to move. If the middle ear is filled with fluid, your doctor will observe little to no movement of the eardrum.
Your doctor may perform other diagnostic tests if there is any doubt about a diagnosis, if the condition hasn't responded to previous treatments, or if there are other persistent or serious problems.
- Tympanometry. This test measures the movement of the eardrum. The device, which seals off the ear canal, adjusts air pressure in the canal, thereby causing the eardrum to move. The device quantifies how well the eardrum moves and provides an indirect measure of pressure within the middle ear.
- Acoustic reflectometry. This test measures how much sound emitted from a device is reflected back from the eardrum — an indirect measure of fluids in the middle ear. Normally, the eardrum absorbs most of the sound. However, the more pressure there is from fluid in the middle ear, the more sound the eardrum will reflect.
- Tympanocentesis. Rarely, a doctor may use a tiny tube that pierces the eardrum to drain fluid from the middle ear — a procedure called tympanocentesis. Tests to determine the infectious agent in the fluid may be beneficial if an infection hasn't responded well to previous treatments.
- Other tests. If your child has had persistent ear infections or persistent fluid buildup in the middle ear, your doctor may refer you to a hearing specialist (audiologist), speech therapist or developmental therapist for tests of hearing, speech skills, language comprehension or developmental abilities.
What a diagnosis means
- Acute otitis media. The diagnosis of "ear infection" is generally shorthand for acute otitis media. Your doctor likely makes this diagnosis if he or she observes signs of fluid in the middle ear, if there are signs or symptoms of an infection, and if the onset of symptoms was relatively sudden.
- Otitis media with effusion. If the diagnosis is otitis media with effusion, the doctor has found evidence of fluid in the middle ear, but there are presently no signs or symptoms of infection.
- Chronic suppurative otitis media. If the doctor makes a diagnosis of chronic suppurative otitis media, he or she has found that a persistent ear infection resulted in tearing or perforation of the eardrum.