An ear infection (acute otitis media) is most often a bacterial or viral infection that affects the middle ear, the air-filled space behind the eardrum that contains the tiny vibrating bones of the ear. Children are more likely than adults to get ear infections.
Ear infections frequently are painful because of inflammation and buildup of fluids in the middle ear.
Because ear infections often clear up on their own, treatment may begin with managing pain and monitoring the problem. Ear infection in infants and severe cases in general often require antibiotic medications. Long-term problems related to ear infections — persistent fluids in the middle ear, persistent infections or frequent infections — can cause hearing problems and other serious complications.
The onset of signs and symptoms of ear infection is usually rapid.
Signs and symptoms common in children include:
- Ear pain, especially when lying down
- Tugging or pulling at an ear
- Difficulty sleeping
- Crying more than usual
- Acting more irritable than usual
- Difficulty hearing or responding to sounds
- Loss of balance
- Fever of 100 F (38 C) or higher
- Drainage of fluid from the ear
- Loss of appetite
Common signs and symptoms in adults include:
- Ear pain
- Drainage of fluid from the ear
- Diminished hearing
When to see a doctor
Signs and symptoms of an ear infection can indicate a number of conditions. It's important to get an accurate diagnosis and prompt treatment. Call your child's doctor if:
- Symptoms last for more than a day
- Symptoms are present in a child less than 6 months of age
- Ear pain is severe
- Your infant or toddler is sleepless or irritable after a cold or other upper respiratory infection
- You observe a discharge of fluid, pus or bloody discharge from the ear
An adult with ear pain or discharge should see a doctor as soon as possible.
An ear infection is caused by a bacterium or virus in the middle ear. This infection often results from another illness — cold, flu or allergy — that causes congestion and swelling of the nasal passages, throat and eustachian tubes.
Role of eustachian tubes
The eustachian tubes are a pair of narrow tubes that run from each middle ear to high in the back of the throat, behind the nasal passages. The throat end of the tubes open and close to:
- Regulate air pressure in the middle ear
- Refresh air in the ear
- Drain normal secretions from the middle ear
Swelling, inflammation and mucus in the eustachian tubes from an upper respiratory infection or allergy can block them, causing the accumulation of fluids in the middle ear. A bacterial or viral infection of this fluid is usually what produces the symptoms of an ear infection.
Ear infections are more common in children, in part, because their eustachian tubes are narrower and more horizontal — factors that make them more difficult to drain and more likely to get clogged.
Role of adenoids
Adenoids are two small pads of tissues high in the back of the nose believed to play a role in immune system activity. This function may make them particularly vulnerable to infection, inflammation and swelling.
Because adenoids are near the opening of the eustachian tubes, inflammation or enlargement of the adenoids may block the tubes, thereby contributing to middle ear infection. Inflammation of adenoids is more likely to play a role in ear infections in children because children have relatively larger adenoids.
Conditions of the middle ear that may be related to an ear infection or result in similar middle ear problems include the following:
- Otitis media with effusion is inflammation and fluid buildup (effusion) in the middle ear without bacterial or viral infection. This may occur because the fluid buildup persists after an ear infection has resolved. It may also occur because of some dysfunction or noninfectious blockage of the eustachian tubes.
- Chronic otitis media with effusion occurs when fluid remains in the middle ear and continues to return without bacterial or viral infection. This makes children susceptible to new ear infections, and may affect hearing.
- Chronic suppurative otitis media is a persistent ear infection that often results in tearing or perforation of the eardrum.
Risk factors for ear infections include:
- Age. Children between the ages of 6 months and 2 years are more susceptible to ear infections because of the size and shape of their eustachian tubes and because of their poorly developed immune systems.
- Group child care.Children cared for in group settings are more likely to get colds and ear infections than are children who stay home because they're exposed to more infections, such as the common cold.
- Infant feeding. Babies who drink from a bottle, especially while lying down, tend to have more ear infections than do babies who are breast-fed.
- Seasonal factors. Ear infections are most common during the fall and winter when colds and flu are prevalent. People with seasonal allergies may have a greater risk of ear infections during seasonal high pollen counts.
- Poor air quality.Exposure to tobacco smoke or high levels of air pollution can increase the risk of ear infection.
Most ear infections don't cause long-term complications. Frequent or persistent infections and persistent fluid buildup can result in some serious complications:
- Impaired hearing. Mild hearing loss that comes and goes is fairly common with an ear infection, but it usually returns to what it was before the infection after the infection clears. Persistent infection or persistent fluids in the middle ear may result in more significant hearing loss. If there is some permanent damage to the eardrum or other middle ear structures, permanent hearing loss may occur.
- Speech or developmental delays. If hearing is temporarily or permanently impaired in infants and toddlers, they may experience delays in speech, social and developmental skills.
- Spread of infection.Untreated infections or infections that don't respond well to treatment can spread to nearby tissues. Infection of the mastoid, the bony protrusion behind the ear, is called mastoiditis. This infection can result in damage to the bone and the formation of pus-filled cysts. Rarely, serious middle ear infections spread to other tissues in the skull, including the brain or the membranes surrounding the brain (meningitis).
- Tearing of the eardrum.Most eardrum tears heal within 72 hours. In some cases, surgical repair is neededYour 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.