Otitis externa

Question 1

What is otitis externa?

Answer 1

Inflammation of the external ear canal

Question 2

What are the 5 types of otitis externa?

Answer 2

Acute or chronic
Localised or diffuse
Malignant

Question 3

How long does acute otitis externa last for?

Answer 3

<3 weeks

Question 4

How long does chronic otitis externa last for?

Answer 4

> 3 months

Question 5

Describe localised otitis externa

Answer 5

Infection of a hair follicle in the ear which develops into a boil

Question 6

Describe diffuse otitis externa

Answer 6

Widespread inflammation of the skin in the external auditory canal

Question 7

What is malignant otitis externa?

Answer 7

Infection spreads to the mastoid and temporal bones causing osteomyelitis

Question 8

What percentage of the UK population develop otitis externa per year?

Answer 8

> 1%

Question 9

What are the risk factors for otitis externa?

Answer 9

Swimming
Humid/warm climates 
Older age
Diabetes
Narrowing/obstruction of the auditory canal 
Over cleaning leading to a lack of wax 
Wax build up 
Eczema
Trauma
Radiotherapy to the ear

Question 10

Describe the pathophysiology of otitis externa

Answer 10

Infection of the skin in the external auditory canal
Bacterial or fungal infection
Bacteria can enter the ear after a blockage of the canal, absence of cerumen after excessive cleaning, trauma or an alteration in pH

Question 11

Name the bacteria which cause otitis externa

Answer 11

Pseudomonas aeruginosa

Staphylococcus aureus

Question 12

What are the 4 main symptoms of otitis externa

Answer 12

Pain
Itching
Discharge
Hearing loss

Question 13

What can be seen on clinical examination of otitis externa

Answer 13

Oedema
Erythema
Exudate
Tympanic membrane 
Pain on movement of tragus or auricle
Pre-auricular lymphadenopathy

Question 14

What investigations can be done for otitis externa?

Answer 14

Usually none

But if persistent or recurrent then swabs for microscopy and culture

Question 15

Describe the management of otitis externa

Answer 15

Avoid getting ear wet
Remove discharge with cotton wool and do not use buds
Remove hearing aids and earrings
Pain killers
Antibiotic or antifungal ear drops
Oral antibiotics if cellulitis present
Chronic otitis externa - corticosteroids and acetic acid

Question 16

List the complications of otitis externa

Answer 16

Abscess
Stenosis of the ear canal due to build up of thick dry skin 
Perforated ear drum 
Cellulitis
Malignant otitis externa