Otorrhoea is the discharge of material from the external auditory meatus. It is both a symptom and a sign. It is not a diagnosis. Otorrhoea may arise from a source in the external ear canal, middle ear cleft, mastoid air cells or intra-cranial cavity.
Otitis externa and active chronic otitis media are the commonest conditions causing otorrhoea. Malignancy is uncommon. The discharge may contain wax, squamous debris, blood (acute otitis media, trauma, neoplasm) and cerebrospinal fluid (CSF), which usually follows a petrous temporal bone fracture.
68.3 Clinical Features
The character of the discharge depends on, and gives clues to, its source.
1. External ear The cardinal symptoms of otitis externa are itch, pain and discharge. There are no mucinous glands in the external canal. Acute inflammatory conditions of the external meatus therefore tend to produce a watery, serous exudate or transudate. In addition, they tend to provoke a hyperkeratosis. This combination leads to soggy white debris collecting in the canal and a thin white, cloudy discharge from the ear. The external canal may also be the subject of trauma, or the site of a furuncle, either of which may lead to bleeding from the ear. A waxy ear discharge is common in children with a pyrexia because of the raised external ear canal temperature creating a more liquefied wax.
2. Middle ear The middle ear cleft is lined by mucosa. Mucosa is, by definition, a lining of one or more layers of non-keratinising squamous epithelium which produces mucous from mucous glands contained within. Thus, if there is a mucoid component to the discharge, it usually arises from the middle ear via a perforation of the tympanic membrane. Trapped keratin is offensive; if a cholesteatoma should become infected, the discharge tends to be particularly unpleasant and once smelt, it is never forgotten. A serosanguineous discharge is common with chronic otitis media should the middle ear mucosa has become granular and polypoid. A sanguineous (meaning blood-stained) discharge is also a feature of carcinoma of the middle or external ear. Chronic otitis media is not typically characterised by pain. Therefore, in patients who have chronic otorrhoea with otalgia that fails to respond to the usual conservative measures, it is wise to consider either bone infection from a localised osteitis or a spreading skull base osteomyelitis (malignant otitis externa) or carcinoma.
3. Cerebrospinal fluid