Ear infections are one of the most common reasons parents take their children to the doctor. While there are different types of ear infections, the most common is called otitis media, which means an inflammation and infection of the middle ear. The middle ear is located just behind the eardrum.

The term "acute" refers to a short and painful episode. An ear infection that lasts a long time or comes and goes is called chronic otitis media.

For links to other types of ear infections, see otitis.

Ear infections are common in infants and children in part because their eustachian tubes become clogged easily. For each ear, a eustachian tube runs from the middle ear to the back of the throat. Its purpose is to drain fluid and bacteria that normally occurs in the middle ear. If the eustachian tube becomes blocked, fluid can build up and become infected.

Anything that causes the eustachian tubes and upper airways to become inflamed or irritated, or cause more fluids to be produced, can lead to a blocked eustachian tube. These include:

• Colds and sinus infections
• Allergies
• Tobacco smoke or other irritants
• Infected or overgrown adenoids
• Excess mucus and saliva produced during teething

Ear infections are also more likely if a child spends a lot of time drinking from a sippy cup or bottle while lying on his or her back. Contrary to popular opinion, getting water in the ears will not cause an acute ear infection, unless the eardrum has a hole from a previous episode.

Ear infections occur most frequently in the winter. An ear infection is not itself contagious, but a cold may spread among children and cause some of them to get ear infections.

Risk factors include the following:

• Not being breast-fed
• Recent ear infection
• Recent illness of any type (lowers resistance of the body to infection)
• Day care (especially with more than 6 children)
• Pacifier use
• Genetic factors (susceptibility to infection may run in families)
• Changes in altitude or climate
• Cold climate

An acute ear infection causes pain (earache). In infants, the clearest sign is often irritability and inconsolable crying. Many infants and children develop a fever or have trouble sleeping. Parents often think that tugging on the ear is a symptom of an ear infection, but studies have shown that the same number of children going to the doctor tug on the ear whether or not the ear is infected.

Other possible symptoms include:

• Fullness in the ear
• Feeling of general illness
• Vomiting
• Diarrhea
• Hearing loss in the affected ear

The child may have symptoms of a cold, or the ear infection may start shortly after having a cold.

All acute ear infections include fluid behind the eardrum. You can use an electronic ear monitor, such as EarCheck, to detect this fluid at home. The device is available at pharmacies.

The doctor will ask questions about whether your child (or you) have had ear infections in the past and will want you to describe the current symptoms, including whether your child has had any symptoms of a cold or allergies recently. Your doctor will examine your child's throat, sinuses, head, neck, and lungs.

Using an instrument called an otoscope, the doctor will look inside your child's ears. If infected, there may be areas of dullness or redness or there may be air bubbles or fluid behind the eardrum. The fluid may be bloody or purulent (filled with pus). The physician will also check for any sign of perforation (hole or holes) in the eardrum.

A hearing test may be recommended if your child has had persistent (chronic and recurrent) ear infections.