Definition of Ear infection - acute:

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.

Causes, incidence, and risk factors:

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