But if the Eustachian tube is blocked because of swelling caused by a cold, a sinus infection, or even an allergy, fluid is trapped in the middle ear. Bacteria thrive in dark, warm, wet places, and a fluid-filled ear is an ideal breeding ground. As the infection worsens, so does the swelling and pain in and around the eardrum. Fever develops as your child's body fights the infection. As children grow to adulthood, the tube triples in length and becomes more vertical, so fluid can drain more easily.
Ear infections are among the most common childhood illnesses.
While no one has compiled statistics on how many toddlers get them, the American Academy of Pediatrics conservatively estimates that most children will have at least one by age 3. Some children have many more than that. Call the doctor at the first sign of an ear infection. He'll ask you to come in so he can take a look in your child's ear with an instrument called an otoscope. An eardrum that's red, bulging, and possibly draining is likely to be infected.