Otitis can affect the inner or outer parts of the ear. The condition is classified according to whether it occurs suddenly and for a short time (acute) or repeatedly over a long period of time (chronic).
When otitis involves the outer ear and ear canal, it is called otitis externa, often called swimmer's ear. A more severe form can spread into the bones and cartilage around the ear.
When otitis involves the middle ear, located just behind the eardrum, it is called otitis media, or ear infection.
An acute ear infection is often painful and most often starts suddenly, lasting for a short period of time.
Chronic ear infection iswhen the ear infection does not go away or keeps coming back. It may cause long-term damage to the ear.
Otitis media with effusion is when there is thick or sticky fluid behind the eardrum in the middle ear, but there is no ear infection.