Necrotizing (Malignant) Otitis Externa

Excerpt

Necrotizing (malignant) otitis externa (NOE) is not cancerous, but it can rapidly spread in a patient's body and has been historically associated with a high mortality rate, hence its name. Toulmouche reported the initial case of malignant otitis external (MOE) in 1838, and MOE was subsequently introduced by Chandler in 1968 due to the high mortality rate associated with the infection during that period. In recent times, MOE has come to be known as necrotizing otitis externa (NOE), a term that more accurately and distinctly characterizes the aggressive and pathological nature of the condition.

NOE is a severe and potentially life-threatening infection that originates in the external auditory canal (EAC). The most common cause of NOE is Pseudomonas aeruginosa, a gram-negative bacterium. Typically, these infections predominantly affect older patients, many of whom have diabetes mellitus. NOE primarily targets the EAC, skull base, and temporal bone, potentially involving the stylomastoid and jugular foramina. Infection and inflammation originating from the EAC can propagate through various anatomical pathways, reaching the mastoid process in the posterior direction, the temporomandibular joint, the parotid gland, and cervicofacial spaces anteriorly, or the skull base medially.

This infection essentially advances from a basic otitis externa, progressing to cellulitis, then chondritis, and ultimately extending to the temporal bone, resulting in periostitis and ultimately culminating in osteomyelitis. NOE can result in serious complications, including the development of cranial neuropathies, brain abscesses, meningitis, and dural venous sinus thromboses. Therefore, healthcare practitioners should maintain a heightened suspicion level for NOE to identify and initiate treatment promptly.