Otitis externa Flashcards
What is the most common pathogen to cause otitis externa?
Pseudomonas aeruginosa (~40% of cases)
What are the bacterial causes of otitis externa?
- Pseudomonas aeruginosa
- Staphylococcus aureus
- Proteus mirabilis
- E. coli
What are the fungal causes of otitis externa?
- Aspergillus (~90% of fungal cases)
- Candida
What are the risk factors for otitis externa?
- Trauma to external auditory canal: cleaning, insertion of foreign objects, excessive itching)
- Increased moisture in the external auditory canal: swimming, humid climate
Other risk factors:
- dermatological issues (eczema)
- down’s syndrome (narrow ear canal)
- diabetes and history of immunosuppression
- previous surgery to ear or radiotherapy to head/neck
What are the clinical features of otitis externa?
Symptoms:
- Severe ear pain, particularly at night
- Otorrhoea
- Intense itching
- Hearing loss
Signs:
- Tragus is tender to touch
- Pulling up and back on the auricle causes pain
- Conductive hearing loss
What are otoscopic findings of localised and diffuse otitis externa?
- Localised: furuncle
- Diffuse: oedematous and reddened external auditory canal
What investigations should be performed for otitis externa?
- Mainly a clinical diagnosis
- Perform cranial nerve examination as facial nerve palsy can be a sign of necrotising otitis externa
- Need to rule out diabetes
- Culture and sensitivity tests are not routinely performed - may be done if abx treatment fails
What is the management of otitis externa?
- Keep ear dry
- Avoid use of cotton bus or itching
- Topical abx ear drops (ciprofloxacin) for 7-14 days + steroid
What are the complications of otitis externa?
- Necrotising otitis externa
- Pinna or peri-auricular cellulitis
What is necrotising otitis externa?
Infection spreading beyond soft tissue of the ear canal resulting in osteomyelitis of the temporal bone and skull base
What treatment should be started if initial management has failed and the infection appears to be spreading?
Oral abx –> Flucloxacillin
