This distinct clinical entity is characterized by a localized ulceration in the skin of the floor of the bony external auditory canal with infection of the exposed bone (osteitis) and sequestration of the underlying exposed tympanic bone.
Although the precise etiology is unclear, benign osteitis of the tympanic bone appears to result from a traumatic laceration and subsequent ulceration of the skin of the deep meatus. This ulceration, if combined with infection, results in necrosis of the underlying periosteum with exposure, infection (osteitis) and ultimately sequestration of the underlying tympanic bone.
Patients with benign osteitis of the tympanic bone are usually elderly and frequently suffer from chronic lung disease.
While the symptoms are minor and variable, the most common symptom is a persistent dull otalgia with or without otorrhoea. Most cases are unilateral, although benign osteitis may occur bilaterally.
Hearing loss (with the exception of presbycusis which is not infrequently encountered in this age group) is not a feature of this disease unless there has been a secondary accumulation of debris within the ear canal.
The typical ulceration in the skin covering the floor of the deep meatus may not be seen until the ear canal has been cleaned and the area debrided. The entire ulcerated area may be covered with a smooth yellowish layer of inspissated serum like exudate which can on first glance resemble cerumen or even normal deep canal skin.
In some patients, fresh granulations and an accumulation of white keratin debris may be found covering the base of the ulcer.
The most appropriate method of treatment depends on the severity of the symptoms, the extent of the osteitis and the general health of the often elderly and debilitated patient.
In most cases, the clinical course of this disease is relatively mild.
Simple transcanal curettage with removal of the sequestrum and granulation tissue with exposure of healthy bone will usually allow re-epithelialization of the cutaneous ulceration and resolution.
Note the ulceration in the skin of the floor of the bony canal. The margins of the ulcer are hyperkeratotic.