Ear Infection

Ear infections develop when viruses, bacteria or other microorganisms affect tissues within or around the ear. Middle ear infections, known as otitis media, often occur after a cold or another upper respiratory infection. The middle ear is connected to the back of the nose and throat by the Eustachian tube, which helps regulate pressure and drain fluid. When this tube becomes swollen or blocked, fluid can accumulate behind the eardrum and create conditions in which infection and inflammation can develop. Children are particularly susceptible because their Eustachian tubes are smaller and more horizontal than those of adults.

Outer ear infections, known as otitis externa or sometimes “swimmer’s ear”, develop in the ear canal rather than behind the eardrum. Moisture remaining in the canal after swimming or bathing can create an environment that encourages bacterial growth. Damage or irritation to the delicate skin of the ear canal — including from inserting cotton buds or other objects — can also increase the risk of infection. Skin conditions affecting the ear canal may make some people more susceptible to repeated inflammation and infection.

Some ear infections resolve relatively quickly, while others can persist or repeatedly return. Enlarged adenoids, recurrent respiratory infections, allergies and problems with Eustachian tube function can contribute to repeated middle ear problems. Fluid may also remain behind the eardrum after an infection has cleared, temporarily causing muffled hearing without necessarily indicating an ongoing infection. Because ear pain can have causes other than infection — including earwax, jaw problems and referred pain from the teeth or throat — persistent or severe symptoms are best assessed rather than assumed to be an infection.