Middle ear infection
Middle ear infections usually occur along with an upper respiratory infection (URI), such as a cold. Fluid builds up in the middle ear, creating a perfect breeding ground for bacteria or viruses to grow into an ear infection.
Pus forms as the body tries to fight the ear infection. More fluid collects and pushes against the eardrum, causing pain and sometimes problems hearing. Fever typically lasts a few days. And pain and crying usually last for several hours. After that, most children have some pain on and off for several days, although young children may have pain that comes and goes for more than a week.
Antibiotic treatment may shorten some symptoms. But most of the time the immune system can fight infection and heal the ear infection without the use of these medicines.
In severe cases, too much fluid can increase pressure on the eardrum until it ruptures, allowing the fluid to drain. When this happens, fever and pain usually go away and the infection clears. The eardrum usually heals on its own, often in just a couple of weeks.
Middle ear fluid buildup
Most children who have ear infections still have some fluid behind the eardrum a few weeks after the infection is gone. For some children, the fluid clears in about a month. And a few children still have fluid buildup (effusion) several months after an ear infection clears. This fluid buildup in the ear is called otitis media with effusion. Hearing problems can result, because the fluid affects how the middle ear works. Usually, infection does not occur.
Otitis media with fluid buildup (effusion) may occur even if a child has not had an obvious ear infection or upper respiratory infection. In these cases, something else has caused eustachian tube blockage.