The Eustachian tubes connect your ears to the back of your throat. When they are working properly, these tubes drain the fluid produced in the middle ear. If the tubes are blocked, the fluid from the middle ear backs up and increases the risk of infection. Ear infections are especially common in babies and children because their Eustachian tubes clog more easily than those of adults. Allergies, tobacco use, sinus infections, and colds can all cause Eustachian tube blockages. People who have overgrown adenoids are also at risk for developing ear infections due to blocked tubes. Several things increase the likelihood of a child developing an ear infection. They include climate changes, exposure to cigarette smoke, pacifier use, altitude changes, and other illnesses. Children who attend daycare also have a higher risk of developing ear infections. Babies and young children are often very irritable when they develop ear infections. Adults and older children usually experience ear pain, temporary hearing loss, fullness in the ear, and general feelings of illness. Some people also have vomiting and diarrhea.