definition of otitis externa
diffuse inflammation of skin and subdermis of ear canal, can include pinna or tympanic membrane
swimmer’s ear or tropical ear
acute = lasts less than 6wks
chronic = >3mo
bugs that cause otitis externa
acute - bacteria
* pseudomonas aeruginosa
* staph aureus
chronic - fungal
* aspergillus
* candida
what is malignant otitis externa
life threatening progressive infection of external ear canal
may spread to cause osteomyelitis of temporal bone and adjacent structures
pseudomonas aeruginosa
RF for acute otitis externa
- skin conditions - eczema/psoriasis/seborrhoeic dermatitis - skin debris -> infection
- acute otitis media
- contact dermatitis
- trauma - ear cleaning remove wax which is natural barrier to moisture and infection
- foreign body insertion
- water exposure
- ear canal obstruction
RF for chronic otitis externa
- skin conditions
- DM / immunocomp
- contact dermatitis
- fungal infection
- bacterial infection - low grade persistent infection -> thickening of ear canal, loss of normal skin structure, reduced ear wax production
causes of malignant otitis externa
- uncontrolled dm / immunocomp
- old age
- radiotherapy to ear/head/neck -> skin atrophy/ulceration and damage to sebaceous glands = reduced wax
- previous ear surgery/irrigation
complications of otitis externa
- chronic
- regional spread of infection -> cellulitis, perichondritis, chondritis, abscess, parotitis
- fibrosis and stenosis of the ear canal
- fibrosis of tympanic membrane
what suggests perichondritis
Erythema and swelling affecting the pinna but sparing the ear lobe
complications of malignant otitis externa
- facial nerve palsy
- osteomyelitis involving mastoid, temporal and basal skull bones
- meningitis
- brain abscess
- sepsis
px of otitis externa
acute - clinical resolution in 10days
chronic - lumen can narrow -> stenosis -> hearing loss
malignant - life threatening
dx of acute otitis externa
At least one typical symptom (usually rapid-onset within 48 hours):
* ear canal itchy
* Ear pain and tenderness of the tragus and/or pinna (often severe), with possible jaw pain.
* Ear discharge
* Hearing loss due to ear canal occlusion
At least two typical signs:
* Tenderness of the tragus and/or pinna.
* The ear canal is red and oedematous, and there may be debris and discharge contributing to swelling and canal occlusion.
* Tympanic membrane erythema
* Cellulitis of the pinna and adjacent skin.
* Conductive hearing loss
* Tender regional lymphadenitis
when to suspect chronic otitis externa
Typical symptoms:
* Constant itch in the ear.
* Mild discomfort or pain (rare).
Typical signs:
* Lack of ear wax in the external ear canal.
* Dry scaly skin in the ear canal, often results in at least partial canal stenosis; or red, moist skin in the ear canal.
* Fluffy, cotton-like debris, hyphae, or dots of black debris - there is fungal infection.
* Conductive hearing loss.
when to suspect malignant otitis externa
Typical symptoms:
- Unremitting disproportionate ear pain, headache, purulent otorrhoea, fever, or malaise.
- Vertigo.
- Profound conductive hearing loss.
Typical signs:
- Systemically unwell, high fever.
- Granulation tissue seen on the floor of the ear canal and at the bone-cartilage junction; exposed bone in the ear canal.
- Ipsilateral facial nerve palsy.
ix for otitis externa
Consider arranging an ear swab for bacterial and fungal MCS if:
* Treatment failure.
* Severe, recurrent, or chronic otitis externa.
* Ear canal occlusion due to swelling and debris, causing difficulty using topical treatment effectively.
* Suspected spread of infection beyond the external ear canal.
mx of acute otitis externa
dont use cotton buds
keep ears clean and dry
* no swimming for 10days
* hair dryer to dry the ear canal after washing/bathing/swimming
* acetic acid drops/spray - morning, eve and after wet for max 7 days
mx RFs
analgesia
clean external canal to aid rx - dry swab secretions, ear irrigation (if tympanic membrane is intact)
consider topical abx +- steroid
oral abx if - immunocomp, severe infection, spread beyong external ear canal
when to follow up after acute otitis externa
- not improving within 48–72 hours
- not fully resolved after 2 weeks
- Symptoms are severe +- cellulitis spreading beyond the external ear canal.
- immunocompromised and at risk of severe infection
- There is ear wax impaction or stenosis of the ear canal which prevents the tympanic membrane being visualized, to check for an alternative cause for symptoms.
mx of chronic otitis externa
advice, RF, analgesia
ear swab bacterial and fungal MCS
dry swabbing and irirgations
if signs of fungal infectiob - topical antifungal (clotrimazole), acetic acid
if bacterial - mx as for acute
**if no sign of bacteria/fungus - topical steroid drops **
follow up if
* sx persist
* immunocomp and risk of malignant otitis externa
