An ear infection is diagnosed by reviewing symptoms, asking about medical history, and examining the ear. A healthcare professional usually uses a lighted instrument called an otoscope to look at the eardrum and ear canal. They may check how the eardrum moves or assess hearing when needed. The examination helps distinguish an infection from other causes of ear pain, pressure, or hearing changes.
Ear pain, a feeling of fullness, fluid coming from the ear, or changes in hearing can have several causes. Diagnosing an ear infection involves finding out which part of the ear is affected and whether signs of infection or fluid are present. The assessment may differ for children and adults, depending on their symptoms, age, and examination findings.
What does a doctor look for during an ear infection examination?
The main step is examining the ear canal and eardrum. A clinician uses an otoscope, a handheld instrument with a light and magnifying lens, to look for changes that may suggest infection. These findings are considered alongside the person's symptoms and medical history rather than used in isolation.
During the examination, the clinician may look for:
- Redness, swelling, or irritation in the ear canal.
- Fluid or discharge in the ear canal.
- Changes in the appearance or position of the eardrum.
- Fluid behind the eardrum.
- Reduced movement of the eardrum when pressure changes are applied.
Not every finding means an infection is present. For example, redness alone is not enough to establish a middle ear infection. The clinician considers the overall examination, symptoms, and whether the findings fit an infection of the outer or middle ear.
How do doctors distinguish outer ear infections from middle ear infections?
The location of the problem matters because the outer and middle ear are examined for different signs. An outer ear infection, often called otitis externa, affects the ear canal. A middle ear infection, known as acute otitis media, occurs behind the eardrum.
Diagnosing an outer ear infection
The clinician examines the ear canal for swelling, redness, discharge, or irritated skin. They may gently press the small flap in front of the ear opening or move the outer ear to see whether this causes discomfort. Pain with these movements can support the assessment of an outer ear problem, but it is not conclusive on its own.
Diagnosing a middle ear infection
The clinician focuses on the eardrum and the space behind it. A bulging eardrum and evidence of fluid in the middle ear can support a diagnosis of acute otitis media when considered with the person's symptoms. Fluid behind the eardrum without signs of an acute infection may instead indicate otitis media with effusion, which is a different condition.
According to the National Institute on Deafness and Other Communication Disorders (NIDCD), middle ear infections involve the space behind the eardrum and may be associated with ear pain, fever, or hearing difficulties. The clinician's examination helps determine whether the findings fit this type of infection.
What is an otoscope, and how does it help?
An otoscope allows a clinician to view the ear canal and eardrum. The examination is usually brief. The clinician may need to reposition the instrument or gently remove visible wax if it blocks the view, depending on what is appropriate and safe.
For suspected middle ear infections, simply seeing a red eardrum is not always enough. The clinician looks for other signs, such as bulging or fluid, and interprets them in context. If the view is blocked by earwax, discharge, or swelling, the examination may be limited and further assessment may be needed.
Can a doctor test how the eardrum moves?
Yes. When the diagnosis is uncertain or fluid behind the eardrum is suspected, a clinician may use pneumatic otoscopy. This method uses a small puff of air to assess how the eardrum moves. Reduced movement can suggest fluid in the middle ear.
Another option is tympanometry, which measures how the eardrum responds to changes in air pressure. A small probe is placed at the ear opening to measure pressure-related changes. Tympanometry can help identify fluid or problems with middle ear pressure, but the result must be interpreted alongside the physical examination and symptoms.
The Merck Manual's overview of secretory otitis media describes the use of examination and tests such as tympanometry to assess fluid in the middle ear. These tests can be especially useful when fluid is suspected but the diagnosis is not clear from a routine examination.
Are hearing tests needed to diagnose an ear infection?
A hearing test is not necessary for every suspected ear infection. A clinician may recommend hearing assessment when hearing changes are noticeable, fluid remains behind the eardrum, symptoms persist, or there is concern about the effect on hearing. Testing can help determine whether sound is reaching the inner ear normally or whether a problem in the outer or middle ear is affecting hearing.
Audiometry is a common type of hearing test. It measures how well a person hears sounds at different pitches and volumes. Younger children may need age-appropriate testing methods. Hearing tests help assess the impact of an ear problem, but they do not independently establish that an infection is present.
Will a doctor need a swab, blood test, or scan?
Most uncomplicated ear infections can be assessed through symptoms and an examination, without blood tests or imaging. Additional tests are considered when the presentation is unusual, the diagnosis remains uncertain, symptoms do not improve as expected, or a complication or another condition is suspected.
Ear swabs and fluid samples
A sample of ear discharge may be collected for laboratory testing in selected cases, such as persistent or recurrent discharge or when a clinician needs more information to guide treatment. Swabbing is not routinely required for every ear infection. A sample may help identify organisms in the material collected, but its usefulness depends on the location and circumstances of the infection.
Blood tests and imaging
Blood tests are not usually needed for an uncomplicated ear infection. Imaging, such as a CT scan, may be considered if the examination raises concern about a complication or infection involving nearby structures. These tests are not standard first steps and are selected according to the clinical findings.
The NHS guidance on ear infections explains common symptoms and when medical assessment is appropriate. A clinician determines whether further investigations are necessary based on the individual presentation rather than ordering every possible test.
How is an ear infection diagnosed in babies and children?
Diagnosing an ear infection in a young child follows the same general principles, but the clinician must account for the child's age and ability to describe symptoms. A baby may show discomfort by crying, feeding less, sleeping poorly, or being unusually irritable. Older children may report ear pain, pressure, or difficulty hearing.
Because these signs can occur with other illnesses, the clinician examines the eardrum and considers the child's recent symptoms and medical history. The clinician may also ask whether the child has had previous ear infections, recent respiratory symptoms, or concerns about hearing or speech development.
According to the U.S. Centers for Disease Control and Prevention (CDC), healthcare professionals diagnose middle ear infections by examining the ear and assessing symptoms. The distinction between an acute infection and fluid remaining after an infection is important because these conditions may need different management.
What information should you share before the examination?
Clear information about the symptoms can help the clinician interpret the examination. Before the appointment, it may be useful to note when the problem began, whether it is getting better or worse, and whether symptoms affect one or both ears. Mention any discharge, hearing changes, fever, dizziness, recent illness, previous ear problems, or treatments already tried.
Also tell the clinician if the person has ear tubes, a known eardrum perforation, previous ear surgery, or a condition that affects the immune system. These details may influence how the ear can be examined and whether additional testing is appropriate.
When should an ear problem be assessed promptly?
Arrange medical assessment if ear pain or discharge persists, symptoms worsen, hearing changes continue, or the problem repeatedly returns. Seek urgent medical care for swelling or redness behind the ear, an ear that appears to stick outward, facial weakness, severe dizziness, a severe headache, or a person who seems very unwell. A baby younger than three months with a temperature of 38°C (100.4°F) or higher needs prompt medical evaluation.
These warning signs do not all point to the same cause, but some can indicate a problem that needs urgent attention. The appropriate timing of assessment depends on age, symptoms, medical history, and the clinician's findings.