“Oto-” means ear, so “otitis” = infection, and “media” means “middle” — Otitis Media (OM) is an infection of the Middle Ear (see Diagrams — Upper Respiratory Tract and Anatomy of the Ear). It can be caused by viruses or bacteria (see Differences Among Germs), but usually when we make this diagnosis, we mean bacteria, and prescribe antibiotics. If we think it’s a virus, we call it a “URI” (upper respiratory infection), which is essentially a Common Cold.
We tell the difference by looking in the ear with the instrument on exam room walls called an otoscope. If the ear drum is bulging and beefy red, that’s bacterial otitis media. Unfortunately, some clinicians diagnose the disease if there’s even the least bit of redness, which is poor form & leads to overuse of antibiotics.
In Europe, it’s common to never treat the disease with antibiotics at first, because many times otitis gets better on its own. But in my mind, that depends on how you diagnose it. If the ear drum is a little red but isn’t bulging, I don’t give antibiotics, but I don’t call it “otitis media” either.
Otitis Media is more common among children than adults, because children get more colds than adults. The cold causes congestion of the Eustachian Tube (see Diagram above); if any normal bacteria from the nose happen to be in it, they can reach the middle ear and multiply. But you can also get Otitis Media without a cold.
Untreated bacterial otitis media can get better on its own. It can also cause the ear drum to rupture, which cures the illness (like draining a skin abscess). Rupture isn’t as bad as it sounds, because the ear drum usually heals on its own, without hearing loss. Even a permanent rupture can persist with normal hearing. However, if the ear drum ruptures at its edge, skin cells can grow into it, causing a “cholesteatoma” which can eventually cause severe hearing loss, and require surgery. In the age before antibiotics were first invented (late 1930s, mainly late 1940s), doctors would stick a needle through the ear drum to drain the middle ear infection.
Chronic Otitis Media
Otitis Media can rarely cause serious complications. It can persist as a chronic infection, with acute flare-ups from time to time. Antibiotics can “cure” the flares, but not completely eradicate the bacteria; permanent hearing loss is a possibility. Such patients often need surgical procedures to preserve hearing, maybe even reconstruction of the ear drum.
Bacteria from the middle ear can get into the bone on rare occasions (Mastoiditis), which requires major surgery. Worst case is if bacteria spread to cause a Brain Abscess, or infection of the inner ear (severe vertigo); these patients have high fevers & are quite ill.