Symptoms and causes

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
  • 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.

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.

Risk factors

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.

Complications

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 needed.