Ear, Nose & Throat (ENT) >
Otitis Externa
“Infection of the external auditory meatus (a.k.a. swimmer’s ear)”
Risk Factors
- Frequent water contact (e.g. swimming)
- Immunocompromised / diabetes (also increased risk of complications)
- Humid environment
- Local trauma (e.g. cotton bud use, hearing aids)
- Presence of ear polyps, psoriasis or eczema
Aetiology
- Most commonly bacteria (pseudomonas, s. aureus)
- Rarely fungi (aspergillus, candida)
Pathophysiology
- Disruption of the protective mechanisms of the external auditory canal (EAC) may lead to pathogen overgrowth and subsequent inflammation.
- Disruption may be caused by:
- Interruption in wax formation (e.g. repeated water exposure)
- Trauma to the EAC (e.g. cotton bud use)
- Blockage of the EAC (e.g. debris)
- This causes swelling, otorrhoea and debris accumulation, which contribute to further entrapment of pathogens and propagation of the inflammatory response.
Clinical Presentation
- Typically presents as progressive unilateral otalgia with purulent otorrhoea
- Patients commonly experience itchiness or a sensation of ear fullness
- Less common symptoms include tinnitus, hearing loss and swelling
- Exam may show swelling and erythema of the EAC, tragal tenderness, otorrhoea
Investigations
- Diagnosis is based on clinical presentation, however, ear swabs should be considered in recurrent, chronic or non-resolving cases to identify the causative organism
Management
- OTC analgesia (paracetamol, ibuprofen)
- Removal of debris from the external auditory canal
- Topical ear drops (e.g. Otomize: neomycin + dexamethasone + acetic acid)
- Avoidance of contributing factors (e.g. swimming
Complications
- Malignant otitis externa: (infection invades bone at the skull base, causing osteomyelitis)