[11] Otitis Externa Flashcards by Elliot Jones

What is otitis externa?

Inflammation of the outer ear

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What does otitis externa include?

Inflammatory conditions of the auricle, external auditory canal and outer surface of the ear drum

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How can otitis externa vary?

Can be local or diffuse and acute or chronic

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How is the ear canal kept clean?

It is self cleaning and clears itself of debris

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How is the ear canal self-cleaning?

Epithelial migration - the skin surface moves laterally from the tympanic membrane towards the ear canal opening

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What is ear wax also known as?

Cerumen

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What does ear wax consist of?

Epithelial cells
Lysozymes
Oily secretions

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What is the role of ear wax?

Cleaning
Lubrication
Protection
Inhibition of bacterial and fungal growth
Prevent water from from reaching the canal skin

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What can ear wax protect the canal from?

Bacteria, dust and insects

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How does ear wax inhibit the growth of bacteria and fungi?

Creates an acidic coat

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How does ear wax prevent water from reaching the canal skin?

It has hydrophobic properties

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Besides wax, what helps to protect the outer part of the ear canal?

Hair

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What is the role of the hair in the outer part of the ear canal?

Prevent objects entering and aid desquamation and skin migration

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What is the underlying pathology of otitis externa?

Disturbance of the lipid/acid balance of the ear canal

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What is the most common cause of otitis externa?

Infection

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What are other potential causes of otitis externa?

Allergy
Irritation
Inflammatory conditions

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Bacteria is responsible for what percentage of infective cases of otitis externa?

90%

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Fungi is responsible for what percentage of infective cases of otitis externa?

10%

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Is bacterial otitis externa usually caused by a single organism?

No, most have multiple organisms involved

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What are the most common bacteria involved in otitis externa?

S. aureus and P. aeruginosa

What virus can cause otitis externa?

Herpes zoster

What is an outer ear herpes zoster infection known as?

Ramsay Hunt Syndrome

What causes of skin inflammation can cause otitis externa?

Seborrhoeic dermatitis
Acne
Psoriasis
Atopic eczema
SLE

What irritants can cause otitis externa?

Topical medications
Hearing aids
Earplugs
Ear trauma from foreign bodies
Water in ear
Chemicals e.g. hair spray/dye

What are the risk factors for otitis externa?

- Hot and humid climate - Swimming - Old age - Immunocompromised - DM - Narrow external auditory meatus - Obstruction of normal meatus - Insufficient wax - Wax build up - Dermatological conditions - Trauma to the ear canal

What can cause a narrow external auditory meatus?

- Hereditary | - Chronic infection

What can cause obstruction of a normal external auditory meatus?

- Keratosis obturans - Foreign body - Hearing aid - Hirsute ear canal

What can often lead to insufficient ear wax?

Over-cleaning

Why can wax-build up lead to otitis externa?

Causes obstruction and retention of water, debris and infectious organisms

What dermatological conditions can increase the risk of otitis externa?

- Eczema - Seborrhoeic dermatitis - Allergic, atopic or irritant dermatitis affecting the ear canal

What trauma to the ear canal can increase the risk of otitis externa?

- Cotton bud use | - Radiotherapy

What are the main symptoms of otitis externa?

- Pain - Itching - Discharge - Hearing loss

What may be seen on examination in otitis externa?

- Erythem, oedem and exudate in canal - Mobile tympanic membrane - Pain on moving tragus or auricle - Periauricular lymphadenopathy

What are the signs of more severe otitis externa?

- Narrowed and obscured ear canal - Hearing loss - Discharge - Regional lymphadenopathy - Cellulitis beyond ear - Fever

When are swabs recommended in otitis externa?

If treatment has failed or the presentation is atypical

Where is the swab in otitis externa best taken from to avoid contamination?

The medial aspect of the ear canal under visualisation

What are the differentials for otitis externa?

- Foreign bodies - Impacted wax - Otitis media - Cholesteatoma - Referred pain from sphenoid sinus, teeth, neck, or throat - Barotrauma - Dermatological disease

What is the aim of treatment in otitis externa?

- Settle symptoms - Cure infection - Reduce risk of recurrence - Prevent complications

What is the most common treatment method for otitis externa?

Topical drops

What other treatment methods can be useful in otitis externa?

Wicking and removal of debris

What should you do if initial treatment of otitis externa fails?

Reconsider diagnosis

When are oral antibiotics indicated in the management of otitis externa?

If there is cellulitis or cervical lymphadenopathy

What do patients with systemic symptoms in otitis externa need?

Same-day ENT review and potentially admission for IV antibiotics

What is chronic otitis externa?

When it is present for > 3 months

How is chronic otitis externa primarily treated?

Identifying the underlying cause and removing it

What should be done if there is no identifiable cause of chronic otitis externa?

7 days of acetic acid 2% drops with corticosteroid drops

If fungal growth is suspected to be the cause of chronic otitis externa what should be prescribed?

Topical antifungal

What are the potential complications of otitis externa?

- Temporary hearing loss - Acute otitis externa becomes chronic - Cellulitis - Necrotising otitis externa