Otitis externa

Overview

• Definition: Inflammation or infection of the external auditory canal (ear canal).

Aetiology/ Risk Factors

• Bacterial: Most commonly Pseudomonas aeruginosa and Staphylococcus aureus.
• Fungal: Aspergillus or Candida species (less common).
• Excessive moisture: Swimming (‘swimmer’s ear’), humid environments.
• Trauma: Inserting objects (e.g., cotton swabs), scratching.
• Eczema or dermatitis of the ear canal.
• Chronic ear disease or middle ear surgery.

Clinical Features

• Otorrhoea (ear discharge).
• Pruritus (itching).
• Pain, especially when the auricle is pulled.
• Hearing loss or a feeling of fullness.
• Erythema and swelling of the ear canal on otoscopic examination.

Investigations

• Ear swab: For microbiology if fungal infection is suspected or not responding to treatment.
• Otoscopy: To assess the ear canal and eardrum.

Management

• Topical antibiotics: E.g., ofloxacin or gentamicin drops.
• Topical corticosteroids: To reduce inflammation.
• Analgesics: Paracetamol or NSAIDs for pain relief.
• Avoidance of water in the ear.
• Fungal infections: Topical antifungals like clotrimazole.
• Cleaning of the ear canal may be required in severe cases.

Complications

• Malignant otitis externa: Infection spreading to surrounding tissues; more common in diabetics and the immunocompromised.
• Chronic otitis externa.
• Cellulitis or abscess of the pinna.

Key Points

• Avoiding moisture and trauma can prevent otitis externa.
• Otitis externa typically presents with pain, discharge, and sometimes hearing loss.
• Appropriate topical treatment often leads to resolution, but it’s crucial to assess for complications or resistant cases.