Viral or bacterial infections can occur in the middle of the ear. These often cause pain, inflammation, and fluid buildup. Treatment typically involves antibiotics.

Ear infections are the most common reason that children visit doctors.

Ear infections are also known as glue ear, secretory otitis media, middle ear infection, or serous otitis media. Outer ear infections are known as otitis externa or swimmer’s ear.

Infections in the ear are well understood, and their common occurrence means that research is frequently carried out.

Fast facts about ear infections

Here are some key points about ear infections:

  • Children are more likely to get ear infections than adults.
  • Most ear infections improve without treatment.
  • Vaccinating a child against the flu can help prevent ear infections.
  • Biofilms of antibiotic-resistant bacteria may be to blame for prolonged and repeated cases of ear infection
  • Secondhand smoke increases the risk of ear infections.
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An ear infection is a bacterial or viral infection of the middle ear. This infection causes inflammation and the buildup of fluid behind the eardrum.

The middle ear is an air-filled space situated behind the eardrum. It contains vibrating bones that convert sound from outside of the ear into meaningful signals for the brain.

Ear infections are painful because the inflammation and buildup of excess fluid increases pressure on the eardrum.

An ear infection can be acute or chronic. Chronic ear infections may permanently damage the middle ear.

Ear infections can cause varying symptoms. In young children and infants, it may be more difficult to identify some symptoms.

Typical ear infection symptoms may include:

  • fever
  • pain inside the ear
  • lack of energy
  • vomiting
  • difficulty hearing
  • discharge from the ear
  • pressure or fullness in the ear
  • itching and irritation in or around the ear

If discharge is present, a person should speak with a healthcare professional.

Young children or infants may also:

  • pull or tug at their ear
  • become irritable or restless
  • not hear or react to certain sounds
  • lose their balance easily
  • lose their appetite

Ear infections are generally divided into three categories.

Acute otitis media (AOM)

AOM is the most common and least serious form of ear infection. The middle ear becomes infected and swollen, and fluid is trapped behind the eardrum. Fever can also occur.

Otitis media with effusion (OME)

After an ear infection has run its course, there may be some fluid left behind the eardrum. A person with OME may not experience symptoms, but a doctor will be able to spot the remaining fluid.

Chronic otitis media with effusion (COME)

COME refers to fluid repeatedly returning to the middle ear, with or without an infection present. This leads to a reduced ability to fight ear infections and has a negative impact on hearing ability.

An ear infection often begins with a cold, flu, or allergic response. These increase mucus in the sinuses and lead to the slow clearance of fluid by the eustachian tubes. The initial illness will also inflame the nasal passages, throat, and eustachian tubes.

The role of eustachian tubes

The eustachian tubes connect the middle ear to the back of the throat. The ends of these tubes open and close to regulate air pressure in the middle ear, resupply air to this area, and drain normal secretions.

A respiratory infection or allergy can block the eustachian tubes, causing a buildup of fluids in the middle ear. Infection can occur due to bacteria or a virus.

The eustachian tubes of young children are smaller and more horizontal than in older children and adults. This means that fluid is more likely to collect in the tubes rather than drain away, increasing the risk of an ear infection.

The role of adenoids

The adenoid is a pad of tissue located at the back of the nasal cavity. They react to passing bacteria and viruses and play a part in immune system activity. The adenoids can sometimes trap bacteria, however. This can lead to infection and inflammation of the eustachian tubes and middle ear.

The adenoids are close to the openings of the eustachian tubes, and if they swell, they can cause the tubes to close. Children have relatively large adenoids that are more active than those of adults. These make children more likely to contract ear infections.

Testing for ear infection is a relatively simple procedure and a diagnosis can often be made based on symptoms and a physical exam.

The doctor will generally use an otoscope, an instrument with a light attachment, to check for fluid behind the eardrum.

A physician will sometimes use a pneumatic otoscope to test for infection. This device checks for trapped fluid by releasing a puff of air into the ear. Any fluid behind the eardrum will cause the eardrum to move less than normal.

If in doubt, the doctor may use other methods to confirm a middle ear infection.

Tympanometry

The doctor uses a device that seals off and adjusts the pressure inside the ear canal. The device measures the movement of the eardrum. This allows the physician to determine the pressure of the middle ear.

Acoustic reflectometry

This method works by bouncing sound against the eardrum. The amount of sound that is bounced back indicates fluid buildup levels. A healthy ear will absorb the majority of the sound, but an infected ear will reflect more sound waves.

Both acoustic reflectometry and tympanometry can help show fluid in the middle ear. However, they do not show whether the fluid is infected.

Tympanocentesis

If an ear infection has not responded well to treatment, a doctor may use tympanocentesis. This procedure involves creating a small hole in the eardrum and draining a small amount of fluid from the inner ear. This fluid can then be tested to determine the cause of the infection.

This procedure is generally done by a specialist and is only useful for adults and older children as it is done while awake.

In some cases, ear infections will clear on their own without antibiotics. However, ear infections that are severe and last longer than 2 to 3 days require antibiotics.

For most middle ear infections, healthcare professionals will typically recommend either delayed antibiotic prescribing or watchful waiting:

  • Delayed antibiotic prescribing: A healthcare professional may write the prescription for antibiotics, but suggest waiting 2 to 3 days before filling it. In that time frame the individual may recover and not require the antibiotics.
  • Watchful waiting: A healthcare professional may recommend keeping an eye on the symptoms for 2 to 3 days before prescribing antibiotics. This gives the body’s immune system a chance to begin fighting off the infection. If symptoms do not improve in that time, the healthcare professional will generally give antibiotics.

If the diagnosis is COME, then a healthcare professional may recommend ear tubes as a part of treatment.

Ear infections are a common issue, especially among children.

Symptoms may include fever, fullness in the ear, discharge, and pain inside the ear. Small children may also tug or pull at the ear and become irritable and restless.

Medical treatment often involves antibiotics. However, in many cases, ear infections clear on their own after a few days.