Causes of Ear Infection

Most ear infections in children start somewhere else - in the nose and throat. A cold or sore throat swells the lining of the Eustachian tube, the thin channel that connects the middle ear to the back of the nose. Once it is blocked, fluid gets trapped behind the eardrum, germs multiply in it, and the result is acute otitis media (a middle ear infection).

Why children get them more than adults

• A child's Eustachian tube is shorter, narrower and more horizontal, so it drains poorly.
• Young children catch many colds a year, and each one is a chance for fluid to get stuck.
• Enlarged adenoids can sit near the tube opening and block it.

Other things that raise the risk

• Bottle-feeding while the baby lies flat, which lets milk travel toward the tube.
• Passive smoke at home.
• Crowded settings such as a crèche or daycare, where colds pass quickly.
• Not being breastfed in the early months, as breastfeeding gives some protection.
• Allergies and a family history of frequent ear infections.

The outer ear is different. Otitis externa, often called swimmer's ear, is an infection of the ear canal skin. Trapped water after swimming or bathing, scratching the canal, and pushing cotton buds or earphones in are the usual causes.

The classical texts call ear disease and link it with aggravated Vata in the ear channels, with cold wind, water in the ear and probing the canal named as triggers. That picture of "water and cold wind" sits close to what modern medicine describes, but it is an interpretive framework, not a lab-proven cause.