Earaches in kids.
They're fairly straightforward really.
The Eustachian tubes of kids are bent, as they wouldn't fit in the heads of kids otherwise.
Adults have straight eustachian tubes.
Being that the tubes are bent, they include a tight corner. In that tight corner you'll find a nice collection of mucus, provided that the kid has been eating mucus-producing foods.
That's milk (the most common culprit, over here), that's sugar, and that's white flour.
The inner ear is a closed system (unless you have a hole in your eardrum). That means that when the mucous membranes of the inner ear produce mucus it'll go down the eustachian tube, get stopped at the tight(ish) corner, and start to collect. Upwards. Increasing pressure in the inner ear.
And that's the most common cause of earaches in kids.
... and people still insist on giving antibiotics for Otitis media. I've seen the statistics, and they ain't pretty, but I don't quite remember them. I think it goes something like this: about 3 times out of 4 there is no microbe involved. About 3 times out of 4 where there is a microbe, it's not a bacteria. Antibiotics work only if there's a bacteria involved ...
So people ask me what to do for their kids' recurrent ear infections. I tell them to ditch all milk products, they tell me "but that's so difficult".
Tell me, if your kid got the runs from milk, would it still be too difficult? No? But you are willing to mess up a developing immune system totally and completely, just because it's so difficult to be different.
Here's what'll happen next: once the head grows large enough (when the kid turns 6 or 7) the kink in the tubes will be gone, and there will be no more ear aches. However, if you've gone the antibiotics route, they won't have a working immune system, and now they'll have asthma instead.
... end of rant.
Some vegan kids get earaches, too. The other mucus-producíng foods are white sugar and white flour. I'm not all that sure about giving growing kids a totally vegan diet, though.
I've seen research on putting tubes into the eardrum, as well. That was done with kids who've had trouble in both ears: they put tubes in just one. The other ear cleared up faster ... and there's always risks with surgery which requires anaesthesia.
And there's the midnight earache. I'll do that one later.