Otitis Externa

Question 1

what is otitis externa?

Answer 1

Inflammation of the skin in the external canal.

Question 2

How long does an infection need to be present for it to be regarded as chronic otitis externa?

Answer 2

Over 3 weeks

Question 3

What is otitis externa colloquially known as?

Answer 3

Swimmers ear

Question 4

What are common causes of trauma to the ear canal and can increase the risk of otitis externa?

Answer 4

Cotton buds
Earplugs

(swimming can also increase risk due to exposure to water)

Question 5

What naturally protects against otitis externa?

Answer 5

Cerumen (ear wax)

Question 6

What are causes of inflammation in otitis externa?

Answer 6

Bacterial infection
Fungal infection
Eczema
Seborrhoeic dermatitis
Contact dermatitis

Question 7

What are the 2 most common bacterial causes of otitis externa?

Answer 7

Pseudomonas aeruginosa
Staphylococcus aureus

Question 8

Describe pseudomonas aeruginosa (gram_ve, aerobic/anaerobic, shape) and where it grows best?

Answer 8

Gram negative, aerobic, rod-shaped bacteria.
Grows in moist, oxygenated environments.

Question 9

Other than otitis externa, what can pseudomonas aeruginosa also cause?

Answer 9

Can colonise lungs in patients with CF, increasing mortality.

Question 10

What can pseudomonas aeruginosa be treated with?

Answer 10

Is naturally resistant to many.
Aminoglycosides like gentamicin
or quinolones like ciprofloxacin

Question 11

How does otitis externa typically present?

Answer 11

Ear pain
Discharge
Itchiness
Conductive hearing loss (if ear becomes blokced)

Question 12

What can examination show in otitis externa?

Answer 12

Erythema and swelling in ear canal
Tenderness
Pus or discharge in ear canal
Lymphadenopathy in neck or around ear.

Question 13

How is otitis externa diagnosed?

Answer 13

Clinically with otoscope examination.

Can use ear swab to identify causative organism

Question 14

How is mild otitis externa treated?

Answer 14

Acetic acid 2% (over the counter- EarCalm)

Can also be used prophylactically

Question 15

Moderate otitis externa is usually treated with a topical ______ and _______

Answer 15

antibiotic and steroid

eg Neomycin, dexamethasone and acetic acid = Otomize spray

Question 16

Before prescribing neomycin (in Otomize ear spray) or any other aminoglycosides, what should be checked?

Answer 16

There is no perforation of tympanic membrane.
Potentially ototoxic and could cause hearing loss if gets past the tympanic membrane.

Question 17

What can be used if the canal is very swollen and treatment with ear drops or sprays will be difficult?

Answer 17

An ear wick.
Made of sponge and contain topical treatment for otitis externa. Inserted and left for some time eg 48 hours.
As swelling settles, ear wick removed and treatment can continue with drops/sprays.

Question 18

What is a life-threatening form of otitis externa?

Answer 18

Malignant otitis externa, when the infection spread to the surrounding bone and progresses to osteomyelitis of the temporal bone.

Question 19

What are risk factors for malignant otitis externa?

Answer 19

Diabetes
Immunosuppressant meds like chemotherapy
HIV

Question 20

What is a key finding indicating otitis externa?

Answer 20

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

Question 21

How is malignant otitis externa managed?

Answer 21

Admission under ENT
IV antibiotics
Imaging CT/MRI to assess extent of infection

Question 22

What are complications of malignant otitis externa?

Answer 22

Facial nerve damage and palsy
Other cranial nerve involvement
Meningitis
Intracranial thrombosis
Death