Overview of Middle Ear Infections in Young Children

Middle ear infection is infection of the space immediately behind the eardrum.

A Look Inside the Ear

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:

• Differences from adults in the size and length of their eustachian tubes

• Increased susceptibility to infection in general

• Increased exposure to infection

• Use of a pacifier

A main risk factor is

• Exposure to cigarette smoke in the household

Other risk factors include a strong family history of ear infections, bottle-feeding (instead of breastfeeding), attending a day care center, and living in an area where resources are low or air pollution is high.

The eustachian tube connects the middle ear with the nasal passages 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 blocking air from reaching the middle ear. 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.

The Eustachian Tube: Keeping Air Pressure Equal

The eustachian tube helps maintain equal air pressure on both sides of the eardrum by allowing outside air to enter the middle ear. If the eustachian tube is blocked, air cannot reach the middle ear, so the pressure there decreases. When air pressure is lower in the middle ear than in the ear canal, the eardrum bulges inward. The pressure difference can cause pain and can bruise or rupture the eardrum.

At about the age of 6 months, infants become generally 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 infections, including ear infections, because breast milk contains the mother’s antibodies.

Also at about this age, children interact more with other children 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 interferes with air reaching the middle ear.

All children have pain in the affected ear (see Earache). Infants with middle ear infection may simply be cranky or have difficulty sleeping. Young children often have fever, nausea, vomiting, and diarrhea.