Acute Otitis Externa

Question 1

What is the definition of acute otitis externa?

Answer 1

Diffuse inflammation of external ear canal

Question 2

What is the age of the children who are commonly affected? What activity is commonly associated and why?

Answer 2

> 2 years
Swimming - local defence mechanisms become impaired by prolonged ear canal wetness and local skin desquamation leads to microscopic fissures that provide portal of entry for infecting organisms.

Question 3

What are some risk factors for AOE?

8

Answer 3

Swimming
Trauma
Foreign body
Hearing aid
Dermatological conditions
Chronic otorrhea
Tight head scarves
Immunocompromised

Question 4

How do kids present with AOE?

Answer 4

Otalgia - 70% (often severe)
Itching - 60%
Fullness - 22%
Hearing loss - 32%
Ear canal pain when chewing

RAPID onset (within 48hours)

Question 5

How do you tell the difference between AOM with otorrhea and AOE?

Answer 5

1. tenderness of the tragus when pushed

2. tenderness of the pina when pulled

Question 6

What are the physical examination findings?

Answer 6

the canal: oedematous and erythematous +/- cellulitis (inflammation out of proportion)
+/- lymphadenopathy

Question 7

What organisms cause AOE?

Answer 7

Pseudomonas aeruginosa
Staph aureus
Many are polymicrobial
Rare: fungal (aspergillus and candida)

Question 8

So you swab everyone?

Answer 8

No - ONLY in unresponsive or severe cases

Question 9

What is the management of mild-moderate AOE?

Answer 9

1. Topical antimicrobials +/- topical steroids (mixed results) x 10 days
2. Pain control (PO meds). Topical meds have mixed effectiveness

NB topical acidifying solutions (Buro-Sol) - equally effective in clinical cure at 1 week, but inferior at 2-3 weeks for clinical and micro cure. Not liscenced in Canada

Question 10

If you choose topical gentamicin, what do you need to ensure first?

Answer 10

That there is no perforation of the tympanic membrane.

Same for neomycin, agents with low PH (acidifying and antiseptic agents) and cortisporin.

Question 11

What do you do if the edema in the ear canal is so severe you cannot see into it and are not sure the deliver of the topical antimicrobials will work?

Answer 11

You can place an expandable wick to decrease canal edema and facilitate antimicrobial delivery

Question 12

When will you start to see improvement?

Answer 12

at 48-72 hours, but full response can take up to 6 days

Question 13

What do you do if the kid does not respond?

Answer 13

Evaluate for obstruction and FB
Evaluate for non-adherence
Evaluate for an alternative diagnosis: contact dermatitis, viral or fungal infection
Swab

Question 14

Which kids are unique and should be treated differently?

Answer 14

Immunodeficient kids and DM

AT RISK of malignant otitis externa - invasive infection of the cartilage and bone of the canal and external ear

Question 15

How can malignant AOE present?

Answer 15

Prominent pain

VII palsy

Question 16

How would you investigate malignant AOE and what pathogens cause it? (2)

Answer 16

CT or MRI

Pseudomonas or aspergillus

Question 17

What are some options for preventing AOE?

Answer 17

Inserting soft, malleable plus into auricle
Removing the water from the ears after swimming
AVOID cotton swabs because they might impact cerumen and hard ear plugs (may cause trauma)
Daily prophylaxis with alcohol or acidic drops during high risk activities - not studied

Question 18

What are some examples of topical antimicrobials?

Answer 18

Ciprodex - cirpofloxacin and dexamethasone: 4 drops BID
Garamycin - gentamicin: 3-4 drops TID
Cortisporin Otic - neomycin + polymyxin + hydrocortisone