H65-H75: Diseases of middle ear and mastoid

H70: Mastoiditis and related conditions

Mastoiditis and related conditions (H70) are infections of the mastoid bone, which is located behind the ear. These conditions occur when a middle ear infection, also known as otitis media, spreads to the mastoid bone. Symptoms typically include pain, redness, and swelling behind the ear, in addition to fever and hearing loss in the affected ear. If not treated promptly, mastoiditis can lead to serious health complications such as hearing loss, blood clot, or infections in the brain. The progression of mastoiditis often begins with a persistent or severe middle ear infection that goes untreated or is resistant to treatment. Various types of bacteria, most commonly Streptococcus pneumoniae and Haemophilus influenza, are known to cause this type of infection. Both the auditory (hearing) system and immune system are affected in these conditions.