How Middle Ear Infections Are Diagnosed

An ear infection happens when the middle ear becomes inflamed and fluid builds up behind the eardrum. Five out of six children will have an ear infection by the time they are 3 years old, making it the most common reason parents bring their child to the doctor.

This article discusses the causes, symptoms, and diagnosis of ear infection. It also includes information about other possible reasons you may have ear pain and redness.

ear infection diagnosis


How Ear Infections Start

Behind your eardrum is a small sac called the middle ear. Connected to the middle ear is your eustachian tube, which drains fluid into the back of your throat.

Ear infections often begin after a child has a cold, sore throat, or upper respiratory infection caused by common bacteria or viruses. The infection can cause the eustachian tube to swell and block fluid from draining.

As the fluid builds up in the middle ear, the virus or bacteria grow and the middle ear becomes infected. Children have narrower eustachian tubes than adults, making them more prone to ear infections.


Some ear infections may cause no symptoms at all and are only diagnosed when a doctor notices fluid buildup behind the eardrum.

The most common type of ear infection—acute otitis media (AOM)—causes ear pain and fever. A child with AOM may be especially fussy and have difficulty sleeping. You may also see them rubbing or tugging at their ear.

In some cases, ear infections can cause hearing loss. They can also make you feel dizzy or off-balance.

Symptoms of AOM tend to come on suddenly. For 80% of children with AOM, symptoms completely resolve within three days without the need for antibiotic treatment.

In very severe cases of AOM that do not resolve, a child can develop meningitis, a condition in which the tissues surrounding the brain become inflamed.

Although rare, children can also develop a bacterial infection in the temporal bones that surround the ear canal. This condition is known as acute mastoiditis.

Early diagnosis and treatment of the ear infection will prevent it from developing into a more serious illness.


Doctors can safely examine ears for infection using an otoscope. This special tool has a light and a lens that help them see all the way to the eardrum without the risk of puncturing it. Usually, this exam is enough to make a diagnosis.

Visual Examination

Between 5% and 10% of children will develop a small tear on their eardrum due to the infection, causing cloudy pus to drain from the ear.

Your doctor will check to see if the eardrum appears cloudy, red, yellow, or swollen. Signs of fluid behind the eardrum or in the ear canal will confirm the diagnosis.

Your doctor may also use a small probe to lightly pulse sound waves against the eardrum. This test is known as tympanometry, and it shows your doctor how well the eardrum moves in response to sound.


In most cases, imaging is not necessary to check for ear infection. However, your doctor may order imaging tests if the ear infection persists despite treatment or if your doctor suspects other complications. Two types of imaging they may order are:

  • Computed tomography scan (CT scan): A CT scan may be used to check for abscesses or other abnormalities in and around your ear.
  • Magnetic resonance imaging (MRI): If your doctor suspects your symptoms are brain-related, they may order an MRI to take a detailed look at your brain.

Ear Infection Doctor Discussion Guide

Get our printable guide for your next doctor's appointment to help you ask the right questions.

Doctor Discussion Guide Child


Ear infections may be caused by a viral or bacterial infection and often clear up on their own within three days. Doctors use an otoscope to examine the ear for infection. A buildup of fluid in the middle ear and pus drainage point to an ear infection.

What Else Could It Be?

Many other ear-related conditions have similar symptoms as an ear infection. For this reason, you should avoid self-diagnosis and have your symptoms checked by a doctor, especially if your symptoms last beyond three days.

The following symptoms are common both in ear infection and other ear conditions:

  • Ear pain: Other causes of ear pain include swimmer's ear, ear trauma, or shingles. Children in particular may have ear pain if they get a small object stuck in their ear.
  • Redness: It's not an ear infection if the eardrum is red but there is no fluid behind the eardrum. Redness may also be caused by upper respiratory infection, crying, high fever, or ear trauma.
  • Decreased motion: If the doctor finds your eardrum does not move in response to pressure like it should, they may suspect another condition like tympanosclerosis, in which calcium builds up on the eardrum.

When to See Your Doctor

Children younger than three months need to see a doctor at the first sign of ear infection. Otherwise, children should be seen if they have one or more of the following symptoms:

  • Their fever is 102.2 degrees or higher
  • Discharge is leaking from their ear
  • Their symptoms get worse or do not resolve within three days
  • They experience loss of hearing

Ear infection in adults may signify a more serious problem and should be checked by a doctor. If the infection comes and goes, schedule an appointment with an otolaryngologist, a doctor who specializes in ear, nose, and throat conditions.


Most cases of ear infection get better on their own without medication. Infections that are severe or persist beyond three days may be treated with an antibiotic like amoxicillin.

Otherwise, your doctor may simply suggest keeping a close eye on the infection to make sure it clears up without new or worsening symptoms.

In the meantime, drinking plenty of water, applying a warm compress to the ear, and taking over-the-counter pain relievers like Tylenol (acetaminophen) or Advil (ibuprofen) can help ease the healing process along.


An ear infection typically begins after a cold, flu, or upper respiratory infection. The bacteria or virus that caused the infection may build up in fluid behind the eardrum, leading to a middle ear infection.

Ear infections are more common in children than adults. In children, the infection generally clears up within three days on its own. If it lasts longer, it should be checked out by a doctor, who will use an otoscope to examine the ear.

Frequently Asked Questions

How can you tell if you have a middle ear infection as an adult?

The most common symptoms of ear infection in adults are:

  • Pain in one or both ears
  • Fluid draining from the affected ear
  • Hearing issues
  • Sore throat
  • Fever
  • Problems with balance

How can a doctor tell the difference between a viral middle ear infection and a bacterial middle ear infection?

The symptoms of a middle ear infection essentially are the same whether they're caused by a virus or bacteria. Lab tests are rarely used to determine the cause. In many cases, both a virus and bacteria are involved.

A Word From Verywell

Figuring out if your child has an ear infection can be quite distressing, as young children can't always express what symptoms they are having. If something seems off with your child, relieve yourself of the guesswork and take them to a doctor.

Your doctor may recommend little more than a warm compress and over-the-counter pain relievers. But when caught early, you'll feel better knowing that your child will be back to their usual self within a few days.

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Article Sources
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