Otorrhea

Otorrhea (from Greek οὖς, “ear”, and ῥέω, “to flow”) is the medical term for any fluid drainage from the external auditory canal. It is not a diagnosis on its own. Instead, it describes a symptom that can occur in a wide range of conditions involving the external, middle, or inner ear, as well as nearby structures.

The appearance of the discharge is an important diagnostic clue. Color, viscosity, and odor can help narrow the cause and suggest where the pathological process is located. For this reason, identifying and treating the underlying condition is essential to prevent complications and to preserve hearing.

Aetiology and Pathophysiology

The causes of otorrhea are diverse. In practice, they are often grouped by the type of exudate.

Main types and typical causes:

• Purulent otorrhea: thick yellow or green discharge, often with a foul odor.
  • Acute otitis media: may occur at the perforative stage, when pus drains through a tympanic membrane perforation.
  • Chronic suppurative otitis media: persistent or intermittent purulent drainage through a chronic perforation. It may also suggest an associated cholesteatoma.
  • Otitis externa: bacterial or fungal infection of the ear canal skin.
• Serous or mucoid otorrhea: clear watery discharge or, conversely, thick, stringy mucus.
  • Otitis media with effusion: otorrhea may occur if there is a tympanic membrane perforation or a tympanostomy (ventilation) tube in place (a “grommet”).
  • Allergic dermatitis of the external auditory canal.
• Bloody otorrhea (otorrhagia): discharge mixed with blood.
  • Trauma: abrasion of the ear canal skin, traumatic tympanic membrane perforation, or head trauma.
  • Acute hemorrhagic (bullous) otitis/myringitis: often associated with influenza.
  • Neoplasms: tumors of the ear (e.g., a glomus tumor/paraganglioma or squamous cell carcinoma).
• Cerebrospinal fluid otorrhea (CSF otorrhea): leakage of clear, water-like cerebrospinal fluid.
  • Basilar skull fracture: an alarming sign that may indicate communication between the subarachnoid space and the middle ear.
  • Postoperative complication: may occur after ear surgery or skull base procedures.

Clinical significance

Any otorrhea should be assessed by an ENT specialist. The workup starts with a focused history. It also includes associated symptoms such as pain, hearing loss, vertigo, and fever. Ear examination is mandatory and is performed with otoscopy or endoscopy.

During the examination, the clinician evaluates the ear canal skin and the tympanic membrane. The goal is to identify the source of the discharge, such as inflammation, a perforation, a polyp, or a tumor. If infection is suspected, a culture of the discharge can be obtained to guide antimicrobial therapy. When middle-ear disease or bony involvement is suspected, audiometry and CT of the temporal bones are commonly used. Treatment is directed at the cause. This may include antibiotics for infection or surgical repair of a tympanic membrane perforation.

Differential Diagnosis

The key diagnostic task is to determine the anatomical source of the discharge. It is important to distinguish otitis externa, where pathology is confined to the ear canal, from otitis media, which typically implies tympanic membrane perforation when otorrhea is present. In addition, hearing loss, tinnitus, or vertigo usually points to involvement of the middle or inner ear. The most critical condition to recognize promptly is CSF otorrhea, which is potentially life-threatening because it increases the risk of meningitis. Any watery ear discharge after head trauma should be treated as CSF leakage until proven otherwise.