Otitis externa

Question 1

What is otitis externa?

Answer 1

inflammation of the skin in the external ear canal

Question 2

Give 5 causes of otitis externa:

Answer 2

1) bacterial infection
2) fungal infection
3) eczema
4) seborrheic dermatitis
5) contact dermatitis

Question 3

Give the fungi known to cause otitis externa:

Answer 3

1) candida
2) aspergillus

Question 4

Why is topical antibiotic use a risk factor for fungal otitis media?

Answer 4

the topic antibiotics can kill ‘friendly’ flora which have a protective effect fungal infections

Question 5

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

Answer 5

1) Pseudomonas aeruginosa
2) Staphylococcus aureus

Question 6

Is Pseudomonas aeruginosa gram positive or gram negative?

Answer 6

gram negative

Question 7

Give 8 presentations associated with otitis externa:

Answer 7

1) ear pain
2) discharge
3) itchiness
4) conductive hearing loss (if the ear gets blocked)
5) erythema and swelling in the ear canal
6) tenderness of the ear canal
7) pus or discharge in the ear canal
8) lymphadenopathy in the neck or around the ears

Question 8

What is the gold standard diagnostic tool for otitis externa?

Answer 8

otoscopy

Question 9

What investigation can be carried out to identify the causative organism in otitis externa?

Answer 9

ear swab

Question 10

What is the treatment for mild otitis externa?

Answer 10

acetic acid 2% (EarCalm)

Question 11

What is the treatment strategy for moderate otitis externa?

Answer 11

topical antibiotics and steroid spray/drops

Question 12

Give 4 combinations of topical antibiotic and steroid used to treat moderate otitis externa:

Answer 12

1) Neomycin and dexamethasone
2) Neomycin and betamethasone
3) Gentamicin and hydrocortisone
4) Ciprofloxacin and dexamethasone

Question 13

True or false: aminoglycosides are otoxic

Answer 13

true

Question 14

Give two examples of aminoglycosides:

Answer 14

1) gentamicin
2) neomycin

Question 15

What essential precaution must be made when prescribing topical aminoglycosides in the ear (and why)?

Answer 15

a perforated tympanic membrane must be excluded as aminoglycosides can cause hearing loss if it passes the tympanic membrane

Question 16

What is the treatment strategy for severe otitis externa?

Answer 16

oral flucloxacillin or clarithromycin

Question 17

What topical medication is used to treat fungal otitis externa?

Answer 17

clotrimazole

Question 18

What is malignant otitis externa?

Answer 18

a severe form of otitis externa that spreads to the temporal bone and can progress to osteomyelitis

Question 19

In which patients is malignant otitis externa most commonly seen?

Answer 19

immunocompromised (diabetics, HIV, chemotherapy)

Question 20

Give 4 presentations associated with malignant otitis externa:

Answer 20

1) severe otitis externa symptoms
2) persistent headache
3) fever
4) granulation tissue at the junction between the bone and cartilage of the ear

Question 21

What is the characteristic examination finding associated with malignant otitis externa?

Answer 21

granulation tissue at the junction between the bone and cartilage of the ear

Question 22

What is the treatment strategy for malignant otitis externa?

Answer 22

1) admit to hospital
2) IV antibiotics
3) CT/ MRI head

Question 23

Give 4 complications of malignant otitis externa:

Answer 23

1) cranial nerve damage
2) meningitis
3) intracranial thrombosis
4) death