ENT

Otitis externa

Inflammation or infection of the external auditory canal, usually managed with ear care, analgesia and topical treatment; severe persistent pain in a person with diabetes or immunosuppression is a necrotising otitis externa emergency.

In a nutshell

Otitis externa is inflamed or infected external-canal skin, usually after water exposure or trauma. Treat with analgesia, aural care and appropriate topical therapy; a perforated tympanic membrane changes drop safety, and severe persistent pain in a diabetic or immunocompromised patient may be necrotising otitis externa.

Classic presentation

Painful itchy ear with discharge, a swollen red canal and pain on tragal or pinna movement after swimming, water exposure or canal trauma.

Key points

The disease is in the external-canal skin; tragal/pinna tenderness and canal oedema support otitis externa over uncomplicated otitis media.
First-line care is analgesia, keeping the ear dry, avoiding trauma and appropriate topical treatment; oral antibiotics are not routine for localised disease.
Use aural toilet or a wick when oedema or debris prevents drops reaching the canal skin.
If there is a perforation, grommet or uncertain tympanic membrane, avoid aminoglycoside/polymyxin drops unless ENT directs them; follow BNF/local non-ototoxic guidance.
Severe deep or nocturnal pain, granulation, cranial-nerve signs or treatment failure in a diabetic/immunocompromised patient suggests necrotising otitis externa.
Swab severe, recurrent, chronic or treatment-resistant disease and involve ENT when there is spread beyond the canal, a mass or persistent discharge.

First-line investigation

Otoscopy with assessment of the canal, tympanic membrane, pinna, mastoid, hearing and cranial nerves; no routine imaging for uncomplicated disease.

Management

Analgesia and ear protection

Give appropriate analgesia, keep the ear dry and stop cotton buds, scratching, swimming and unprescribed drops.^1,2

Topical therapy and aural care

Use appropriate topical acetic acid or antibiotic/steroid treatment; arrange aural toilet or a wick when oedema or debris prevents penetration.^1,3,4

Protect the tympanic membrane

Use non-ototoxic guidance for a perforation, grommet or uncertain membrane and avoid aminoglycosides unless ENT directs their use.^1,5,6

Recognise necrotising or spreading disease

Escalate spreading cellulitis, systemic illness or severe persistent pain with granulation/cranial-nerve signs in a high-risk host urgently to ENT and hospital care.^1,3,7

Review treatment failure and recurrence

Swab or refer persistent, recurrent, severe or atypical disease; reconsider fungal, dermatological, middle-ear, foreign-body and structural causes.^1,3,2

Exam traps

Pain on tragal movement points to external-canal disease; it is not a reason to diagnose otitis media.
A perforated tympanic membrane or grommet makes aminoglycoside-containing drops potentially ototoxic.
Oral antibiotics do not replace topical therapy for uncomplicated localised otitis externa.
Granulation and severe persistent pain in a diabetic patient should trigger urgent assessment for necrotising otitis externa.
Do not keep escalating drops without removing obstructing debris, checking the membrane and reconsidering the diagnosis.

Illustrations

Otitis externa with a discharging ear canalClinical photograph of an inflamed external auditory meatus with purulent discharge and debris in otitis externa.Klaus D. Peter, Wiehl, Germany, Wikimedia Commons · CC-BY-3.0-DE

Severe otitis externa with inflammatory crusting and granulation around the ear canalClinical photograph of granulation tissue on the floor of the ear canal at the bony-cartilaginous junction, a red-flag sign of necrotising otitis externa.James Heilman, MD, Wikimedia Commons · CC-BY-3.0

Key sources

This page is exam revision material, not medical advice, and must not be used for patient care. Always check drug doses against the BNF and current guidance. Full disclaimer.