It's not unusual for a baby or toddler to get ear infections. Ninety percent of children have at least one ear infection by the time they're 2 years old, according to one study. Children are most at risk for ear infections between 6 and 18 months, although about half of all kids get their first ear infection before 6 months.
Fortunately, the rate of ear infections declines after age 3. However, there are some things that put your child at a greater risk for ear infections even beyond age 3.
For example, frequent ear infections tend to run in families. In the same way blue eyes or athletic ability is inherited, how well your ear muscles open and close is also passed on. Children with allergies are also prone to ear infections. The congestion caused by exposure to dust or pollen blocks the eustachian tube so that it can't drain. This can quickly lead to an ear infection when germs invade.
Babies who are born with a cleft palate or Down syndrome are also more likely to get ear infections. The differences in their anatomy make it harder for their eustachian tubes to function properly.