Otitis media is an infection of the middle ear (the space behind the eardrum). Ear infections are the most common illnesses in babies and young children. Otitis media usually occurs in children under 3 years of age. Actually three out of four children experience otitis media at some stage.
Boys tend to get ear infections more often than girls. There are two main types. The first type is called acute otitis media (AOM). This means that parts of the ear are infected and swollen. AOM can be painful. The second type is called otitis media with effusion (fluid), or OME. This means fluid and mucus stay trapped in the ear after the infection has gone.