Alternate Names : Otitis media – acute, Infection – inner ear, Middle ear infection – acute
Definition
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.
Overview, Causes, & Risk Factors
For each ear, a eustachian tube runs from the middle ear to the back of the throat. This tube drains fluid that is normally made in the middle ear. If the eustachian tube becomes blocked, fluid can build up. When this happens, germs such as bacteria and viruses can multiply and cause an infection.
Ear infections are common in infants and children, in part because the eustachian tubes become easily clogged. 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:
- 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 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 ear infections include the following:
- Not being breastfed
- 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
Adults can also have ear infections, although they are less common than in children.
Pictures & Images
Ear anatomy
The ear consists of external, middle, and inner structures. The eardrum and the three tiny bones conduct sound from the eardrum to the cochlea.
Middle ear infection (otitis media)
Otitis media is an inflammation and/or infection of the middle ear. Acute otitis media (acute ear infection) occurs when there is bacterial or viral infection of the fluid of the middle ear, which causes production of fluid or pus. Chronic otitis media occurs when the eustachian tube becomes blocked repeatedly due to allergies, multiple infections, ear trauma, or swelling of the adenoids.
Eustachian tube
Ear infections are more common in children because their eustachian tubes are shorter, narrower, and more horizontal than in adults, making the movement of air and fluid difficult. Bacteria can become trapped when the tissue of the eustachian tube becomes swollen from colds or allergies. Bacteria trapped in the eustachian tube may produce an ear infection that pushes on the eardrum causing it to become red, swollen, and sore.
Mastoiditis – side view of head
Mastoiditis is an infection of the bony air cells in the mastoid bone, located just behind the ear. It is rarely seen today because of the use of antibiotics to treat ear infections. This child has drainage from the ear and redness (erythema) behind the ear over the mastoid bone.
Mastoiditis – redness and swelling behind ear
Mastoiditis is an infection of the bony air cells in the mastoid bone, located just behind the ear. It is rarely seen today because of the use of antibiotics to treat ear infections. This child has noticeable swelling and redness behind his right ear because of mastoiditis.
Ear tube insertion – series
Normal anatomy
The eardrum (tympanic membrane) separates the ear canal from the middle ear.
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Ear infection – acute : Overview, Causes, & Risk Factors
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Ear infection – acute : Symptoms & Signs, Diagnosis & Tests
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Ear infection – acute : Treatment
Review Date : 6/2/2009
Reviewed By : Neil K. Kaneshiro, MD, MHA, Clinical Assistant Professor of Pediatrics, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
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