What Causes A Middle Ear Infection?

The most common ear infection cause is the middle ear infection. 90% of the middle ear infections spread from the nose to the ear through the eustachian tube. What causes middle ear infection is a common cold or bacterial infection or chronic sinusitis. The secretions or phlegm from the nose travels to the back of the nose, called the nasopharynx. The middle ears open into the nasopharynx through the eustachian tube, i.e., designed to move air into the middle ear. When a person blows out his nose, it increases pressure in the nasopharynx. This pressure can push the phlegm from the nasopharynx into the middle ear through the eustachian tube.