Otitis media is a common childhood disease, with risk factors of low socioeconomic status and repeated exposure to other children.

The middle ear, mastoid and pneumatized petrous bone communicate, and are extensions of the upper respiratory tract. Bacteria from the nasopharynx can reflux via the eustachian tube.

The vast majority of patients with acute otomastoiditis are successfully treated with antibiotics without the necessity of imaging. If imaged, non-specific debris within the middle ear and mastoid is seen, possibly with several fluid levels. Importantly, the integrity of the mastoid septae, ossicular chain, and internal and external mastoid cortices are preserved. As fluid can be found in the mastoids of asymptomatic individuals, the diagnosis of acute mastoiditis with air-fluid levels in the mastoid is a clinical diagnosis.

If mucoperiosteal disease extends into the bone, coalescent mastoiditis is diagnosed. This is characterized by erosion of mastoid septae with the development of an intramastoid empyema. This can only be diagnosed with imaging, and high resolution CT is the study of choice.

Complications of coalescent mastoiditis include direct extension to form a subperiosteal abscess, perimastoid edema and cellulitis, and necrosis of the mastoid tip allowing spread of infection inferiorly, deep to the fascial planes that surroud the sternocleidomastoid and trapezius muscles. The result is a Bezold abscess.