Ear Infections | Overview


How does the ear work?

The ear works by receiving sound waves and sending messages to the brain. The outer ear includes the part of the ear you can see and the ear canal. The sound waves go through the ear canal and hit the eardrum and cause it to vibrate.

The vibration of the eardrum causes the tiny bones in the ear to move. This movement sends the sound waves to the inner ear.

What causes earaches?

A tube called the eustachian (say: "you-stay-shun") tube connects the middle ear with the back of the nose. Normally this tube lets fluid drain out of the middle ear. If bacteria or viruses infect the lining of the eustachian tube, the tube gets swollen and fills with thick mucus. This keeps fluid in the ear from draining normally. Bacteria can grow in the fluid, increasing pressure behind the eardrum and causing pain.

The eustachian tubes can become blocked because of allergies, a cold or other infection. In other cases, the adenoids (glands near the ear) become enlarged and block the eustachian tubes.

Acute ear infections usually clear up within 1 or 2 weeks. Sometimes, ear infections last longer and become chronic. After an infection, fluid may stay in the middle ear. This may lead to more infections and hearing loss.

Why are earaches so common in children?

Ear infections may be more common in children because their eustachian tubes are shorter and more narrow than those of adults. Most children will have at least 1 ear infection by their third birthday.

What is otitis media with effusion?

Otitis media with effusion means that there is fluid (effusion) in the middle ear. The middle ear is the space behind the eardrum. Fluid in the middle ear usually doesn't bother children. It almost always goes away on its own in a few weeks to a few months. So, this kind of ear problem doesn't usually need to be treated with antibiotics, unless the fluid doesn't go away.

What is swimmer's ear?

Swimmer's ear (also called otitis externa) is a type of ear infection. It is an infection of the outer ear and the ear canal. Because the canal is dark and warm, it can easily get infected with bacteria and fungus. Swimmer's ear is different from the kind of infection you get in the middle part of your ear. That kind of infection is called otitis media.


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Written by familydoctor.org editorial staff

Reviewed/Updated: 07/13
Created: 01/99