Otitis Media (Ear Infection)

What Is It?

Otitis media is an inflammation and infection of the middle ear (the membrane-lined chamber behind the eardrum). It often is related to an inflammation or infection of the throat or Eustachian tube (the passageway that connects the middle ear to the back of the throat).

Under normal circumstances, the Eustachian tube helps to equalize pressure between the throat and the middle ear. However, when the opening of the Eustachian tube is inflamed or obstructed (usually because of allergies or a throat infection), the normal ventilation of the middle ear is disrupted, leading to pressure changes and an accumulation of fluid inside the middle ear. Bacteria travel up the Eustachian tube from the throat and multiply in this accumulated fluid, resulting in a middle ear infection. Most ear infections are caused by viruses rather than bacteria.

Otitis media is currently the most common illness in children in the United States and the second most common illness in the general population (adults and children combined). Before age 3, approximately 85 percent of children will have at least one episode of this infection, and 50 percent will have at least two. After age 6, episodes of otitis media become much less frequent, possibly because of the child's maturing immune system and normal growth-related changes in the ear and throat.

Symptoms

Inside the middle ear, three ossicles (tiny bones) normally conduct sound vibrations from the eardrum to the inner ear, where they are converted into the nerve impulses for "sound." In patients with otitis media, however, inflammation and infection interfere with this normal mechanism for sound conduction, causing decreased hearing. Infection-related pressure changes and fluid accumulation also produce significant ear pain. Other symptoms may include fever; general body discomfort; rubbing or pulling of the ears (in children); and vomiting and diarrhea (in infants).

Because otitis media is often related to a throat infection, symptoms of otitis media may begin a few days after a sore throat, with or without nasal symptoms (stuffiness, runny nose).

Diagnosis

Your doctor will ask about ear pain, discharge from the ear and fever. He or she will examine the ears with an otoscope — an instrument with a lighted, cone-shaped end piece for inspecting the eardrum and ear canal. Your doctor will look for redness and bulging of the eardrum and to see if the eardrum moves. (Eardrums will not move if they are too stiff or if there is fluid behind them.) A pneumatic otoscope (an otoscope that can blow a tiny puff of air) may be used to check for fluid accumulation.

Expected Duration