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.

An acute ear infection is a short and painful ear infection. For information on an ear infection that lasts a long time or comes and goes, see: Chronic ear infection.

Causes, incidence, and risk factors:

The Eustachian tube runs from the middle of each ear to the back of the throat. This tube drains fluid normally made in the middle ear. If the eustachian tube becomes blocked, fluid can build up. This can lead to infection.

Ear infections are common in infants and children, because the eustachian tubes become easily clogged.

Ear infections may also occur in adults, although they are less common than in children.

Anything that causes the eustachian tubes to become swollen or blocked causes more fluids to build up in the middle ear behind the eardrum. These causes include:

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

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. However, getting water in the ears will not cause an acute ear infection, unless the eardrum has a hole from a previous episode.

Acute ear infections occur most often in the winter. You cannot catch an ear infection from someone else, but a cold may spread among children and cause some of them to get ear infections.

Risk factors for acute ear infections include:

• Attending daycare (especially those with more than 6 children)
• Changes in altitude or climate
• Cold climate
• Exposure to smoke
• Genetic factors (susceptibility to infection may run in families)
• Not being breastfed
• Pacifier use
• Recent ear infection
• Recent illness of any type (lowers resistance of the body to infection)