Otitis externa

Otitis externa is infection and inflammation of the auricle and auditory canal (external ear).

Risk factors

  • This is commonly associated with swimming- the water washes out the ear wax and the resulting environment is suitable for bacterial/fungal growth.
  • Other risk factors include tropical climate, local trauma (e.g. use of cotton buds); eczema/dermatitis/psoriasis etc and absence of cerumen (wax)

Causal organisms

  • Pseudomonas aeroginosa is the most common, followed by Staphylococcus aureus, anaerobes gram-negative organisms (proteus/E coli) and fungal infections such as Aspergillus niger/Candida albicans.
    • Aspergillus infection causes a classical otomycosis characterised by white hyphae growing on the skin

Presentation

The patient may complain of otalgia, aural fullness, itching, discharge (initially clear and non-odourous but can progress to foul-smelling and purulent), conductive hearing loss and occasionally tinnitus.

On examination the ear canal may be tender on tragal manipulation, the ear may be erythematous/oedematous with purulent discharge.  Under the discharge and debris will be red, painful skin.

Management

Scrupulous oral toilet and irrigation is very important (and future ear hygiene e.g. drying the ear properly after a swim).  Otitis externa will usually resolve itself after this without any need for antimicrobial treatment.

A swab may be sent to microbiology in case the problem does not resolve.

If it does not resolve:

  • Topical steroid and Antibiotic (meomycin/gentamicin/polymyxin B/framycetin)IF bacterial cause
  • Topical nystatin/clotrimazole IF fungal cause

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