A. Ear infections in children are caused by infectious agents, usually one of several bacteria, although viruses are responsible in as many as 40 percent of cases studied. Next to colds, otitis is the most common infection in childhood. About 80 percent of children will have at least one episode of otitis by age 3. The middle ear is located between the eardrum and the inner ear. The eustachian tube, which drains mucus and fluid from the middle ear and also regulates pressure between the eardrum and atmospheric air, is a short tube between the middle ear and the nasal passages.
Babies have small eustachian tubes angled in such a way that drainage is poor.
The seasonal incidence of ear infections parallels that of colds and flu. We don't know why one baby with a cold gets an otitis media while another does not, but we do know that some children seem prone to get an earache with every cold. There are actually two types of otitis media that doctors and parents have to know about. The child, who usually but not always has a cold, wakes up screaming in pain and pulling at the ear. The child usually, but not always, has a fever.