Ear infection is very common among children. Up to 95 percent of children suffer through at least one ear infection by age seven. Until their small skulls grow, the Eustachian tubes — one per ear forming a passageway from middle ear to back of throat — aren’t very efficient at draining, making for a convenient bacteria superhighway. An ordinary cold virus can trigger a secondary infection in the ears. So can allergens or irritants that cause congestion and clog the tubes.

An acute ear infection often causes pain, fever and irritability, a surefire recipe for a thoroughly miserable child. But this triad of symptoms doesn’t show up in all cases. Some kids signal a problem by pulling at their ears — if they’re old enough to reach for them. Others might eat less. A toddler with a fluid-filled ear canal may have a tendency to teeter over.

The general rule is that the younger the child, the less able he is to indicate where the problem is and the less specific the symptoms can be.

A child over the age of two may be able to communicate that her ear hurts. By school age, she may even tell you that she can’t hear properly. If your child is also just getting over a cold, consider it another clue.

A doctor can diagnose otitis media (ear inflammation) with an otoscope. If infected, the eardrum will appear inflamed and may bulge. And though it’s usually bacteria partying in your child’s ears, the inflammation could also be due to a virus, which is untreatable with antibiotics.

Pediatricians once reached for their prescription pads at the first sign of a red ear — just in case bacteria was the culprit. That was before worries about drug-resistant superbugs. Increasingly, doctors now take a wait-and-see approach, mostly in cases where the child is older than two years and fever is mild. Various studies support this strategy, showing no greater risk of complications.

If you opt to wait it out on a doctor’s recommendation, be prepared to clear your calendar for a couple of days so you can keep a close eye on your kid. Watch for changes such as a spiking fever (39ºC/102ºF) or pain that isn’t relieved with acetaminophen, which may mean the infection is getting worse.

Whether or not antibiotics are prescribed, the main focus of home treatment is to control the pain, so stock up on acetaminophen or ibuprofen for the first day or two. Keep your child well hydrated, and make sure she gets plenty of rest.

Regardless of risk factors for ear infections, some kids just seem to get loads of them. The shape of their Eustachian tubes may be more prone to blockage, or their immune systems may be immature.

The vaccine Prevnar — which is now included in routine infant immunizations — may also help, protecting your child against seven subtypes of pneumococcus bacteria. In addition, it appears to offer some protection against middle ear infections as well as nastier complications like meningitis. And it lessens the chances she’ll need ear tube surgery.

If your child does suffer through more than her fair share of ear infections, be heartened to know that they’ll slack off as she grows, usually by age seven.

Causes

Why do so many babies and toddlers get sore ears?

One reason is the size and slope of their Eustachian tubes, the tiny tunnels connecting the back of the nose and throat to the middle ear space. Babies and toddlers have shorter, straighter, less slanted Eustachian tubes than older children, which means bacteria and viruses don’t have to travel far to reach the middle ear. The walls of these channels (which stiffen with age) are flexible early in life, which means they easily collapse, preventing normal drainage of fluid produced by cells inside the ear.

Secondly, little people spend lots of time lying down, promoting pooling of fluid in the middle ear. (Bottle-feeding in a prone position increases the likelihood of liquid trickling into the ear.)

Finally, kids in this age group haven’t built up resistance to common germs like cold and flu viruses. These respiratory infections — which they pick up at daycare, playschool and anywhere else they’re in contact with other kids — can cause the Eustachian tubes to swell and become blocked, allowing the microscopic culprits to multiply in the accumulated moisture.