Otitis Media (with Effusion) | Causes & Risk Factors


What causes otitis media with effusion?

Fluid may build up in the middle ear for several reasons. When a child has a cold, the middle ear may produce fluid just like the nose does. A tube called the eustachian (say: "you-stay-shee-an") connects the middle ear with the back of the nose. Normally, the eustachian tube lets fluid drain out of the middle ear. However, bacteria or viruses can infect the lining of your child’s eustachian tube causing it to swell. The adenoids (glands near the ear) can also become enlarged and block the eustachian tubes. It is also not a good idea to let your baby fall asleep with a bottle or to leave a bottle in the crib. Drinking while lying down can actually wash bacteria from the throat right into the eustachian tubes and middle ear space, increasing risk for tube blockage and infection.

If the eustachian tubes are blocked, fluid in the ear cannot drain normally. If bacteria grow in the middle ear fluid, an effusion can become a middle ear infection (acute otitis). This will usually increase pressure behind the eardrum and cause a lot of pain. The eardrum will become red and bulging. If this happens, your child may need to be treated with antibiotics. Children who have frequent ear infections can also develop otitis media with effusion after their infection is gone if the fluid stays in the middle ear.

FDA Warning

The. U.S. Food and Drug Administration (FDA) advise against the use of ear candles. Ear candles can cause serious injuries and there is no evidence to support their effectiveness. For more information, please visit the FDA Web site.


See a list of resources used in the development of this information.

Written by familydoctor.org editorial staff

Reviewed/Updated: 05/16
Created: 01/99


Otitis Media (with Effusion)



Causes & Risk Factors