Middle ear infection is infection of the space immediately behind the eardrum.
Middle ear infections (otitis media) may occur in older children and adults (see Otitis Media (Acute)) but are extremely common among children between the ages of 3 months and 3 years. These infections often accompany the common cold. Young children are particularly susceptible to middle ear infections for several reasons:
Other important risk factors include
The eustachian tube connects the middle ear with the nasal passages (Fig. 1: The Eustachian Tube: Keeping Air Pressure Equal) and helps balance air pressure in the middle ear with that in the environment. In older children and adults, the tube is relatively vertical, wide, and rigid, and secretions that pass into it from the nasal passages drain easily. In infants and younger children, the eustachian tube is more horizontal, narrower, less rigid, and shorter. Thus, the tube is thought to be more likely to become blocked by secretions and to collapse, trapping the secretions in or close to the middle ear and preventing ventilation of the middle ear (that is, blocking air from reaching it). Also, the secretions may contain viruses or bacteria, which multiply and cause infection. Or viruses and bacteria can move back up the short eustachian tube of infants, causing middle ear infections.
At about the age of 6 months, infants become more susceptible to infection because they lose protection from their mother's antibodies, which they received through the placenta before birth. Breastfeeding seems to partially protect children from ear infections because breast milk contains the mother's antibodies.
Also at about this age, children become more sociable and may acquire viral infections after touching other children and objects and then putting their fingers in their mouth and nose. These infections may in turn lead to middle ear infections. Attendance at child care centers increases the risk of exposure to the common cold and hence to middle ear infections.
Using a pacifier may impair the function of the eustachian tube and thus interfere with air reaching the middle ear.
Infants with middle ear infection may simply be cranky or have difficulty sleeping. Young children often have fever, nausea, vomiting, and diarrhea.
To detect a middle ear infection, doctors look in the ear with an otoscope and examine the eardrum for bulging and redness.
Middle ear infections can resolve relatively quickly (acute middle ear infection—see Acute Middle Ear Infection in Children), or they can recur or persist over a long time (chronic middle ear infection—see Chronic Middle Ear Infection in Children). Antibiotics are not always needed (see Secretory Otitis Media in Children).
Last full review/revision June 2014 by Udayan K. Shah, MD