Fighting the Germs
Anatomy alone doesn't cause ear infections. Germs are necessary too. There are two major germ classes that cause infections: bacteria and viruses. Bacteria are responsible for about 70 percent of ear infections, viruses cause about 8 to 25 percent, and bacteria and viruses working in concert are found in the remaining cases. Ear infections that are caused by viruses can't be treated with antibiotics, in the same way that no medicine can cure the common cold. But antibiotics can fight bacterial infections.
The only way your physician can tell if an infection is caused by a virus, bacteria, or both is to remove some of the fluid from the middle ear with a small needle. I don't often do this in my practice, because it takes 48 hours to get lab results back, and parents usually want a quicker response. When a child comes in, if he is fairly ill, I treat him with antibiotics as if he has a bacterial infection. And in children younger than 2, immediate action is critical. Untreated ear infections can spread and cause serious -- even life-threatening -- problems, such as a brain abscess or meningitis. Another rare but serious complication in young children is facial paralysis if the infection spreads to the facial nerve.
A less dangerous and more common consequence of untreated ear infections is a perforated eardrum. The fluid in the middle ear builds up until the pressure causes the eardrum to burst. Although this is frightening to parents, it results in immediate relief from the pain the child was experiencing and lets the fluid drain from the middle ear. Most of these perforations heal on their own, but some do require surgical repair.