How Middle Ear Infections Are Diagnosed

ear infection diagnosis
© Verywell, 2018

Properly diagnosing an ear infection, also known as acute otitis media (AOM), shortens the duration of discomfort, is important to avoid overuse of antibiotics, and helps to prevent worsening infection. Aside from a thorough health history, your physician will likely only need to use a pneumatic otoscope to diagnose an ear infection.

Because young children can't always tell you what is wrong, finding out whether or not your child has an ear infection can be quite distressing as a parent. Fortunately, a trained physician can usually identify an ear infection without much difficulty. Also note that even if you didn't have an ear infection as a child, you can still get one as an adult.

Self-Checks and At-Home Testing

You do not need to be a doctor in order to purchase the supplies needed to do an effective ear exam. However, it is not encouraged unless you know what you are doing, as there are subtleties to assessing the tympanic membrane (as described below).

Children also are notorious for not being cooperative during an ear exam. Without proper equipment and technique, there is a risk of accidentally perforating the eardrum if you insert anything too far into the ear.

However, there are companies that are making it easier for a quick check that you may find helpful before visiting your doctor. There are some smartphone attachments that will allow you to visualize the ear canal and tympanic membrane. There have also been some devices developed that will try to provide a scale of the level of fluid behind your tympanic eardrum; though the accuracy seems to be questionable based on online reviews.

Visual Examination

During the visit with your doctor, it will be important for them to examine your ear. Otoscopy is an exam performed with an otoscope that will allow for the visualization of your external ear canal and your eardrum (tympanic membrane).

While you can perform a basic assessment with a standard otoscope, it is best if your doctor has the pneumatic attachment for the otoscope. The pneumatic attachment is simply a rubber bulb that allows your doctor to apply light pressure to your tympanic membrane. Here is what your physician will be looking for in a normal eardrum:

  • Position - the tympanic membrane will be in a flat or neutral position
  • Translucency - the tympanic membrane is typically translucent
  • Motion - the tympanic membrane will move with application of pneumatic pressure (both positive or negative pressure) from the bulb on the otoscope
  • Color - the typanic membrane will appear pearly gray or pink

Findings that are suggestive of abnormalities in your inner ear include:

  • Position - the tympanic membrane is either bulging or retracted
  • Translucency - the tympanic membrane is opaque or cloudy
  • Motion - the tympanic membrane doesn't respond appropriately to pneumatic pressure when using the bulb on the otoscope
  • Color - gray, blue, amber, white, or pale yellow are all abnormal colors associated with the tympanic membrane.

Your physician will typically diagnose you with an ear infection if they see a bulging tympanic membrane

Imaging

You will not need any imaging for a standard work-up of an ear infection. However, if the infection is prolonged and your doctor is worried about other complications, they may order a CT scan or an MRI.

A CT scan can be useful in seeing the structures, abscesses, or other abnormalities around your ear. An MRI, on the other hand, is useful if your physician is concerned about any problems related to your brain. The use of CT or MRI would be rare and will not be part of a typical evaluation.

Differential Diagnoses

When assessing whether or not you have an ear infection, your doctor will try to differentiate if you have acute otitis media (ear infection) or otitis media with effusion (OME, non-infected fluid in the ear). Both can appear very similar.

Color, motion, and translucency may be variable between both AOM and OME. However, the position of the tympanic membrane is generally the tell-tale sign. In AOM, the tympanic membrane is typically bulging, while it is usually retracted with OME.

Redness

Redness of your tympanic membrane without signs of fluid behind the eardrum is not caused by an ear infection. Your physician may also look at these common causes of redness around the tympanic membrane:

  • upper respiratory infection causing inflammation of the respiratory tract
  • crying
  • elevated fever
  • ear trauma
  • recent removal of ear wax

Decreased Motion

Testing for mobility of the tympanic membrane is important for the identification of middle-ear effusion (MEE - fluid in your middle ear). However, decreased mobility does not mean that the fluid in the middle ear is infected. Other causes of having decreased mobility of your tympanic membrane include:

Ear Pain

Having ear pain is a common symptom of an ear infection. However, there are many other reasons for experiencing ear pain including:

Because of the many different diagnoses that can occur with symptoms of an ear infection, it is always important to follow up with a physician for proper diagnosis.

View Article Sources
  • Acute otitis media in adults. UpToDate website. http://www.uptodate.com (subscription required). Updated April 19, 2017.
  • Acute otitis media in children: Diagnosis. UpToDate website. http://www.uptodate.com (subscription required). Updated October 13, 2017.
  • Lieberthal, AS, Carroll, AE, Chonmaitree, T, Ganiats, TG, Hoberman, A ... Tunkel, DE. (2013). The Diagnosis and Management of Acute Otitis Media. Pediatrics 131(3), e964-e999.
  • Ponka, D & Baddar, F. (2013). Pneumatic otoscopy. Can Fam Physician. 59(9):962.