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.
Symptoms
The onset of signs and symptoms of ear infection is usually rapid.
Children
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
- Headache
- Loss of appetite
Adults
Common signs and symptoms in adults include:
- Ear pain
- Drainage of fluid from the ear
- Diminished hearing
Causes
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.
Related conditions
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.