When your child is stuffed up with a lousy cold, most of the gunk drains from her nose into her throat. But some of it also gets backed up behind the tympanic membrane, also known as the eardrum, which is a little window that opens into the middle ear, explains Oregon-based pediatrician Whitney Casares, M.D., author of The Newborn Baby Blueprint.
Fluid that gets into this tricky spot is supposed to drain into the throat via the eustachian tubes, but that’s not always what happens. Kids’ ears and immune systems are also immature, making them more susceptible to infections.
Anatomy is the main reason little ones are afflicted with ear troubles. Their eustachian tubes are shorter than they are in grown-ups, and they tend to be oriented more horizontally, so it’s harder for fluid to drain out. Bacteria that already live in the back of your child’s nose (gross but true) then make their way into that fluid and breed, says James Coticchia, M.D., a pediatric ENT with The Studer Family Children’s Hospital at Sacred Heart, in Pensacola, Florida. The same thing can happen if your child gets stuffy thanks to the flu or allergies, though colds are the most common trigger for ear infections.
“Plus, not all kids have the ability to blow their nose,” Dr. Casares says. “When adults feel pressure building up, they reach for a tissue.”
Blame heredity, the environment, and plain old bad luck. If you had lots of ear infections when you were young, your child could be more prone, says Dr. Casares. Genetics also controls the size and positioning of the eustachian tubes. Other factors include whether your little one attends day care—kids who do are at higher risk to develop recurring ear infections, says Dr. Coticchia—as well as the age at which he got his first ear infection.
(If your child had one before his first birthday, he’s more apt to have a bunch more.) Children who weren’t breastfed may also get more infections. Breast milk contains antibodies called IgA, which strengthen your child’s defenses against all sorts of bugs.
“Ear infection” is the common term; your doctor knows it as otitis media, and there are three main types. Acute otitis media is the most common, and it means there’s an infection in the middle ear. When a doctor takes a peek with an otoscope, she will see redness and a bulging eardrum, says Elisa Song, M.D., holistic pediatrician with Whole Family Wellness, in Belmont, California.
Sometimes there’s still fluid trapped behind the eardrum after an acute infection seems to have gone away; that’s called otitis media with effusion. The third kind, chronic otitis media with effusion, means that fluid is stuck in the middle ear for an extended period of time or it keeps coming back even when there’s no infection.
In case you were wondering, swimmer’s ear is totally different: It’s an infection in the outer ear that’s caused by bacteria in water that your child is exposed to while—you guessed it—swimming.
RELATED: Help for Swimmer's Ear
Washing his hands frequently can help prevent him from getting sick. When he does have a cold, keep him upright as much as possible (older kids can sleep with an extra pillow behind their head), which will encourage fluid in the ears to drain down, Dr. Casares says. You can also run a humidifier in his room and put saline mist in his nose to thin out mucus and help it flow more easily.
Last, make sure your child is up to date on vaccinations—especially the pneumococcal vaccine. Before this became available, 80 percent of kids got at least one ear infection; now it’s down to 60 percent, according to research published in Pediatrics. You’ll also want to make sure your kid gets a flu vaccine every year, and keep him away from tobacco smoke (it irritates the eustachian tubes).
Fortunately, kids’ risk for ear infections drops off dramatically around age 8. Since the eustachian tubes grow along with the rest of the body, says Dr. Casares, any fluid that makes its way into the middle ear is less likely to get stuck there.