context: If you travel on airplanes -- especially with little ones -- you probably know about ear barotrauma, even if you don't recognize the name. It's that clogged-up, sometimes-painful feeling you get in your ears when the air pressure changes quickly. It's the biggest health problem for people who fly. And it can be especially painful for babies and young kids because their ears aren't fully developed. Ear barotrauma also can happen when you ride in an elevator or drive in the mountains. And it can happen in the water, too. Scuba divers call it "ear squeeze." Your ears are especially sensitive to changes in air and water pressure. The small space in the middle ear behind your eardrum is connected to the back of your nose and throat by a tiny canal called the Eustachian tube. That space is filled with air that's constantly absorbed into the lining of your middle ear and then filled back up through the Eustachian tube. This keeps the air on both sides of your eardrum the same. Air pressure is higher close to the ground. So when an airplane begins to land, the air pressure inside the cabin goes up. To stay equal, the pressure inside your middle ear also needs to rise. That means air has to travel quickly up the Eustachian tube into your middle ear. If your tubes are blocked -- because of a cold, for example -- it can't get there. When the air that was in the middle ear gets absorbed, there's nothing to refill it. This creates a vacuum, and your eardrum is sucked inward and stretched. Small children have ear barotrauma more often because they have narrower tubes. The same thing can happen underwater. The deeper you dive, the higher the pressure. Your ears may start to feel uncomfortable even if you go down just a few feet. Common symptoms include: Stuffed feeling in your ears Muffled hearing because your ear drum can't vibrate and make sound the way it should Ear pain If you hear a "pop" in your ears, that's a sign your Eustachian tubes are open. If they stay blocked, your middle ear can fill with clear liquid to try to balance the pressure. If your Eustachian tubes are closed, it can't drain. In this case, more serious symptoms can happen: Extreme ear pain Dizziness called vertigo A busted eardrum -- fluid or blood leaking from your ear is a sign Hearing loss Your doctor will look inside your ears with a tool called an otoscope. He'll check to see if there's fluid behind your eardrum or if it's damaged. If it is, it may take weeks to heal and you might not hear very well. Usually, the only treatment is time. If it isn't better in 2 months, you may need an operation to prevent lasting hearing loss. Go to a doctor right away if you feel like you're spinning or falling (vertigo) and your symptoms happened right after flying or diving. It's rare, but you may need emergency ear surgery. With a mild case, your symptoms should go away shortly after you get back on land. If they don't or if your symptoms are serious, see your doctor. You can prevent ear barotrauma by keeping your Eustachian tubes open. These things may help: Medicine. If you have a cold or allergies, take a decongestant about an hour before your flight and take it as directed until you land. A nasal spray or an antihistamine could help open up the tubes, too. Earplugs. Special plugs designed for air travel can slow pressure changes and give your ears time to adjust. These won't work for scuba divers, though. If your ears feel full or hurt, try the following: Don't sleep through the landing -- yawn or swallow to try to "pop" your ears. Suck on hard candies or chew gum. Bring a water bottle on board and drink throughout the flight. The swallowing will help keep the Eustachian tubes open and the water may help thin mucus. " Equalize" your ears. Pinch your nose closed, inhale through your mouth, and then gently try to blow air through your nose until you hear a "pop." If you're with a baby, sit her up and give her a bottle or pacifier when the plane begins to land. If you're a diver, try these things to protect your ears: Equalize your ears before your dive and while going down into the water. Go down feet first -- it can make equalizing easier. Look up -- extending your neck can open your tubes. Get back to the surface slowly if you feel pain -- continuing your dive can injure your ears.