Otitis media is a build-up of fluid in the middle ear, the space between the eardrum and the inner ear.
The middle ear is usually filled with air. Sometimes it gets filled with fluid or mucus, for example during a cold. This mucus can sometimes get infected with bacteria, and this is called an ear infection.
Acute otitis media is a short-term ear infection that often comes on suddenly.
Chronic otitis media is when ear infections keep coming back or one infection lasts for a very long time. It often has less severe symptoms so the infection may be unnoticed and untreated for a long time, which means it can cause more damage than an acute infection.
Glue ear is a type of chronic otitis media and happens when the middle ear becomes full of fluid. Glue ear doesn't usually lead to fever, earache or pus coming from the ear.
