Active chronic otitis media affects 0.5 per cent of adults and has two main variants. The first is when there is a squamous epithelial retraction pocket or cholesteatoma. The second variant is when the disease is primarily of the mucosa of the middle ear and mastoid air-cell system. Classically a cholesteatoma is considered ‘unsafe’ because of the risk of complications, particularly intracranial infectioa Mucosal disease, on the other hand, is considered ‘safe’ because complications are thought to be rare. Surgery in the form of a modified radical mastoidectomy is considered to make active chronic otitis media ‘safe’.

A retrospective review of 26 consecutive brain abscesses considered secondary to active chronic otitis media revealed that a cholesteatoma was present in 12 (46 per cent), mucosal disease in 10 (38 per cent) and a modified radical mastoidectomy had been performed in four (15 per cent). Mucosal disease and a modified radical mastoidectomy should no longer be considered ‘safe’. However, the risk of developing an intracranial abscess from any type of active chronic otitis media is low, in the region of one in 3,500.