Acute otitis media is an infection of the middle ear - the usually air-filled space between the tympanic membrane (eardrum) and the bone of the inner ear. Most infections will resolve without treatment or with oral antibiotics, while a small percentage will not improve with conservative treatment and may develop complications, which may include facial weakness /paralysis, infection in or around the brain (meningitis or epidural abscess), perforation of the tympanic membrane, vertigo, abscesses (pockets of pus) around the ear or neck, or severe hearing loss. These cases may be treated more aggressively with intravenous antibiotics and / or surgery - usually starting with a myringotomy (puncturing the eardrum and draining the pus) or mastoidectomy (opening the bone behind the ear to drain pus).

Chronic otitis media may be an infection of the middle ear (the usually air-filled space between the tympanic membrane (eardrum) and the bone of the inner ear) lasting more than 12 weeks, or chronic inflammation of the middle ear with or without cholesteatoma (cyst formed by collapse of the eardrum and accumulation of debris). Most patients with chronic otitis media will also have a perforation of the tympanic membrane (eardrum). A small percentage of cases may develop complications with may develop complications, which may include facial weakness / paralysis, infection in or around the brain (meningitis or epidural abscess), perforation of the tympanic membrane, vertigo, abscesses (pockets of pus) around the ear or neck, or severe hearing loss. Some cases of chronic otitis media may be treated with antibiotics (topical drops, oral, or intravenous depending on the bacteria responsible). Other cases may require surgery to drain pus or remove chronically inflamed or infected tissue from the middle ear and / or mastoid bone and to repair the perforated eardrum.