This is probably one of the questions I get asked about the most by parents.
The anatomy of the ear as shown above is broken into the inner, middle and outer ears. Infections of the inner ear occur around the vestibular and cochlear nerves and are not so common, but can cause problems with balance and infections in the brain (scary). Infections of the outer ear (otitis externa, or swimmer's ear) are caused by getting things into the ear, like water or trauma to the ear from foreign objects (ahem, Q-tips). Middle ear infections (otitis media for us medical folk) are one of the most common infections in childhood and about 75% of kids will have one at some point.
Let's have a little primer about what sets kids up for more ear infections compared to adults.
1. Children have shorter, more horizontal ear canals compared to adults, which makes it easier for bacteria to flourish.
2. Kids have weaker immune systems.
3. Kids have lovely huge tonsils and adenoids compared to adults which can block the Eustachian tubes and increase your risk for a bacterial infection.
Things that increase the likelihood of having a kid get an ear infection are bottle feeding, smoking, day care attendance and having school age siblings. Other factors include giving a baby the bottle while he is laying on his back in a crib or having prolonged cold symptoms. Some people just inherit funny shaped ear canals that predispose them to ear infections. Ear infections are more common during the winter season and spring because of increased allergy and infection exposure. This is what we see in the ear when we look with that funny light.
What you are seeing is the lovely yellow pus behind the eardrum. It hurts like hell and it can cause your kid to be feverish, cranky and a host of other symptoms.
How do you treat them? It sort of depends on the situation. In a kid who is having a lot of pain, fever, decreased appetite, etc, the standard of care is high-dose Amoxicillin (the pink bubblegum stuff). There is now a movement in community pediatrics thought to do a "watch and wait" approach. Many kids with mild ear infections with few symptoms will get better on their own with just Tylenol, Motrin and 24-48 hours of time. Of course, if you show up in my ER, you will probably get antibiotics, because if you are willing to get your kid up at 1 AM and pay a $150 ER copay, I think I can spare you a prescription :-)
To answer the question (I sure can go on a tangent) they are not any more contagious than a regular cold. However, if you have a bunch of toddlers running around rubbing their bacteria-filled boogers all over each other, keep an eye out for the symptoms!