Other Etiologies

While the vast majority of otorrhea is infectious in etiology, there are a number of other important causes. Trauma can cause otorrhea in several different fashions. Head injury or surgery can create a CSF leak from the middle fossa or posterior fossa into the mastoid. The CSF can then pass into the middle ear and escape through the tympanic memberane (TM), if it, too, is damaged or opened by the traumatic event or surgery. More commonly, trauma will be associated with bloody otorrhea due to damage to the eardrum or external auditory canal. This type of otorrhea is often associated with head injury, digital manipulation of the external canal, or removal of cerumen from the ear.

A number of systemic diseases have been associated with otorrhea. The classic systemic etiology associated with otorrhea is Wegener's. Approximately 20% of individuals with Wegener' s granulomatosis will have otologic involvement. Wegener' s can cause inflammation and granulation tissue in the external ear and/or the middle ear, and both sites will be associated with a discharge. In addition to Wegener' s disease, aural discharge has been associated with Churg-Strauss syndrome (Chapter 8) and Behcet's syndrome (Chapter 3) (24,25). Churg-Strauss syndrome produces otorrhea in much the same fashion as Wegener's by forming granulation tissue. In Behcet's disease, the evidence suggests that aural discharge occurs as a result of opportunistic infections.

Tuberculosis (TB), although technically infectious in etiology, can often be associated with an aural form. Although the classic description of TB otitis media is a single central perforation with profuse, painless discharge (26,27), the disorder can cause a host of otologic complications, many of which will also present with otorrhea. A more detailed discussion of TB can be found in Chapter 12.

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