Ear infection (middle ear)

DEFINITION

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.

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 and inflammation.

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 more active and 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 suppurative otitis media is a persistent ear infection that results in tearing or perforation of the eardrum.

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

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
• 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.