Otitis Externa

Question 1

Otitis externa pathophysiology

Answer 1

Inflammation of the external ear canal

Question 2

Otitis externa presentation

Answer 2

• red, swollen, or eczematous with shedding of the scaly skin.
• Discharge may be present in the ear canal
• Pruritis
• Severe otalgia
• Tender over jaw
• Lymphadenopathy

Question 3

Causes of otitis externa

Answer 3

• bacterial infection
• fungal infection
• Seborrhoeic dermatitis
• Contact dermatitis
• Trauma

Question 4

Otitis externa prognosis

Answer 4

Symptoms usually improve within 48–72 hours of initiation of treatment

Question 5

Acute vs chronic otitis externa

Answer 5

Acute - lasts 3 weeks or less

Chronic - lasts longer than 3 months

Question 6

Malignant (necrotising) otitis externa

Answer 6

Aggressive infection that predominantly affects people who are immunocompromised

Otitis externa spreads into the mastoid or/and temporal bone - osteomyelitis

Question 7

Common causative organism of otitis externa

Answer 7

Bacterial:
Psuedomonas aeruginosa
Staphylococcus aureus

Fungal:
Aspergillus
Candida
Deep - trichophyton

Question 8

Mx of otitis externa

Answer 8

Conservative:

• Analgesia and heat pad
• Clean external auditory canal

Medical:
- Otomize Ear Spray - topical abx + corticosteroid- minimum of 7 days

• Oral antibiotics for severe infection - 7-day course of flucloxacillin or clarithromycin

Question 9

Treatment for chronic fungal otitis externa

Answer 9

Topical antifungal - Acetic acid spray or clotrimazole

7-day course of a topical corticosteroid without antibiotic

Question 10

When are oral antibiotics indicated in otitis externa

Answer 10

Cellulitis extending beyond the external ear canal.

Ear canal occluded by swelling and debris, and a wick cannot be inserted

People with diabetes or compromised immunity, and severe infection or high risk of severe infection, for example with Pseudomonas aeruginosa

Question 11

Otitis externa due to Psuedomonas aeruginosa management

Answer 11

Treated with aminoglycosides e.g. gentamicin

or quinolones e.g. ciprofloxacin

Question 12

When is Psuedomonas aeruginosa otitis media commonly seen

Answer 12

Children with cystic fibrosis

Question 13

Diagnosing otitis externa

Answer 13

Otoscopy

Ear swab (not required)

Question 14

Otomize spray

Answer 14

Neomycin, dexamethasone and acetic acid

Question 15

Caution with topical aminoglycosides

Answer 15

Aminoglycosides are potentially ototoxic, cause hearing loss if they get past the tympanic membrane

Therefore exclude a perforated tympanic membrane before using topical aminoglycosides in the ear

Question 16

Ear wick

Answer 16

Used if the canal is very swollen and treatment with ear drops or sprays will be difficult.

Sponge or gauze that contains topical treatment (e.g., antibiotics and steroids).

Inserted and left for 48 hours

As the swelling settles, the ear wick can be removed and treatment can continue with drops or sprays

Question 17

Symptoms of malignant otitis externa

Answer 17

Symptoms are more severe than otitis externa, with persistent headache, severe pain and fever

Question 18

Examination finding for malignant otitis externa

Answer 18

Granulation tissue at the junction between the bone and cartilage in the ear canal

Question 19

Management of malignant otitis externa

Answer 19

Emergency management with:

Admission to ENT team

IV antibiotics

Imaging - CT or MRI head

Question 20

Complications of malignant otitis externa

Answer 20

Facial nerve damage and palsy

Other cranial nerve involvement (e.g., glossopharyngeal, vagus or accessory nerves)

Meningitis

Intracranial thrombosis

Death