What causes an ear infection?

What causes an ear infection?

Ear infections are caused by bacteria and viruses. Many times, an ear infection begins after a cold or other respiratory infection. The bacteria or virus travel into the middle ear through the eustachian tube (there’s one in each ear). This tube connects the middle ear to the back of the throat. The bacteria or virus can also cause the eustachian tube to swell. This swelling can cause the tube to become blocked, which keeps normally produced fluids to build up in the middle ear instead of being able to be drained away.

Adding to the problem is that the eustachian tube is shorter and has less of a slope in children than in adults. This physical difference makes these tubes easier to become clogged and more difficult to drain. The trapped fluid can become infected by a virus or bacteria, causing pain.

Medical terminology and related conditions

Because your healthcare provider may use these terms, it’s important to have a basic understanding of them:

• Acute otitis media (middle ear infection): This is the ear infection just described above. A sudden ear infection, usually occurring with or shortly after cold or other respiratory infection. The bacteria or virus infect and trap fluid behind the eardrum, causing pain, swelling/bulging of the eardrum and results in the commonly used term “ear infection.” Ear infections can occur suddenly and go away in a few days (acute otitis media) or come back often and for long periods of time (chronic middle ear infections).
• Otitis media with effusion: This is a condition that can follow acute otitis media. The symptoms of acute otitis media disappear. There is no active infection but the fluid remains. The trapped fluid can cause temporary and mild hearing loss and also makes an ear infection more likely to occur. Another cause of this condition is a block in the eustachian tube not related to the ear infection.
• Chronic suppurative otitis media: This is a condition in which the ear infection won’t go away even with treatment. Over time, this can cause a hole to form in the eardrum.