Most ear infections form in the middle ear. The eustachian tube carries fluid from the middle ear to the throat. Sometimes during a cold, the eustachian tube becomes swollen and fluid is trapped in the middle ear. Bacteria or viruses can grow in this fluid and form an ear infection.
ByHealthwise StaffPrimary Medical ReviewerSusan C. Kim, MD - PediatricsKathleen Romito, MD - Family MedicineE. Gregory Thompson, MD - Internal Medicine