Otitis Externa Flashcards
What is Otitis Externa?
- Inflammation of outer ear (auricle, external auditory canal, outer surface of eardrum)
What is acute diffuse OE also known as?
- swimmer’s ear
What are the RF for OE?
- Hot and humid climates.
- Swimming.
- Older age.
- Immunocompromise (eg, HIV).
- Diabetes mellitus.
- Narrow external auditory meatus
- Obstruction of normal meatus - eg, keratosis obturans, foreign body, hearing aid
- Insufficient wax
- Wax build-up
- eczema,
- irritant dermatitis
- Trauma to ear canal - eg, from cotton buds, radiotherapy.
- active otitis media,
- Pseudomonas aeruginosa or fungi.
- Previous tympanostomy.
How does insufficient wax cause OE?
- Too little cerumen (often through over-cleaning)
- Reduces the protective function of cerumen
- canal pH rise.
- predispose to infection
How does wax build up cause OE?
- excessive cerumen
- lead to obstruction, retention of water and debris, and infection.
What is cerumen (ear wax) compost of?
- epithelial cells
- lysozymes
- oily secretions from sebaceous and ceruminous glands
What is the function of cerumen?
- cleaning
- lubrication
- protection from bacteria, dust and insect
- creates an acidic coat which also helps to inhibit bacterial and fungal growth
- hydrophobic properties also prevent water from reaching the canal skin and causing maceration
What causes OE?
- Bacterial infection (90%)
- Pseudomonas Aeruginosa
- Staph aurues
- Fungal infection (10%)
- Aspergillus
- Herpes zoster - Ramsay Hunt syndrome
- Skin inflammation
- Seborrhoeic dermatitis
- Acne
- Psoriasis
- Atopic eczema
- SLE
- irritants
- hearing aids, swimming, cotton buds
What are the sx of OE?
- Ear specific
- pain
- itching
- hearing loss
- discharge
What are the findings of OE on otoscopy?
- Ear canal with erythema, oedema and exudate.
- Mobile tympanic membrane.
- Pain with movement of the tragus or auricle.
- Pre-auricular lymphadenopathy
What are the sx and signs of acute diffuse OE?
- Moderate temperature (less than 38°C)
- lymphadenopathy.
- Swelling is diffuse.
- Pain
- pruritus.
- Moving the ear or jaw is painful.
- slight thick discharge, +/- bloody
- Hearing may be impaired.
What is swimmer’s ear also known as?
Do you have to be a swimmer to get this?
- acute OE brought on by water remaining in ear after swimming
- no
What are the RF for chronic OE?
- fungal infection
- immunocompreomised
- diabetes
- prolong abx ear drop use
What is necrostising otitis externa?
- life-threatening extension of otitis externa into the mastoid and temporal bones
What organism commonly causes necrotising OE?
- P. Aeuruginosa
- Staph aureus
What are the sx of necrotising OE?
- Pain and headache of greater intensity than clinical signs would suggest
- Oedema.
- Exudate.
- Granulation tissue (may be present at the junction of bone and cartilage)
What ix would you perform for OE?
- Swabs - if tx failure
- Assess integrity of tympanic membrane
How do you test whether tympanic membrane has perforated?
- Can taste medication placed in the ear; or
- Can blow air out of the ear when the nose is pinched; or
- Has a tympanostomy tube in situ
What are the differential diagnosis of OE?
- Foreign body
- Impacted wax
- Otitis media
- Cholesteatoma
- Chronic suppurative otitis media
How would you mx acute OE?
- topical drops
- removal of debris
- oral abx if
- cellulits
- cervical lymphadenopathy
How would you mx chronic OE?
- acetic acid 2% - 7 days + corticosteroid eardrops
- clotrimazole (topical antifungal) if fungal growth suspected
- tacrolimus
How would you mx malignant OE?
- Quinolones (6-8 weeks)
- Urgent referral to ENT
What are the cx of OE?
- temporary hearing loss/muffling
- cellulitis
- necrotising OE
