Otitis Externa (OE)
Otitis externa (OE) is diffuse inflammation of the skin and subdermis of the external auditory canal; the pinna and tympanic membrane (TM) may also be involved. Acute OE denotes symptoms lasting less than 6 weeks. Chronic OE is persistent or recurrent inflammation lasting more than 3 months.
Necrotising (malignant) OE is a progressive infection that may invade soft tissue and bone (temporal bone osteomyelitis) and is potentially life‑threatening (NICE NG98; PHE/MoD summaries).
Clinical context
- OE is common in urgent and emergency settings.
- Typical triggers include water exposure (swimming), canal trauma (cotton buds, hearing aids), dermatitis of the canal and prior topical antibiotic use.
- Diabetes and other causes of immunosuppression increase the risk of severe or necrotising disease (PHE; MoD synopsis).
Presentation and examination
Typical features
- Severe otalgia, often worse with pinna traction or tragal pressure.
- Purulent otorrhoea, aural fullness and conductive hearing loss from canal oedema and debris.
- Pruritus and local tenderness.
Key examination findings
- Pain on pinna traction or tragal pressure helps distinguish OE from otitis media.
- Erythema, oedema and purulent debris within the canal; canal narrowing may prevent visualisation of the tympanic membrane.