Paediatric Acute care Guidelines PMH Emergency Department

Otitis externa is an infection of the external ear canal, and is also referred to as “swimmer’s ear”

Background

  • The ear canal guards against infection by producing a protective layer of cerumen (ear wax), which creates an acidic and lysozyme-rich environment. While a paucity of cerumen allows for bacterial growth, an excess can cause retention of water and debris, which can create an environment ideal for bacterial invasion.
  • Otitis externa is a common cause of ear pain
  • It has a lifetime incidence of 10%
  • Peak incidence is in children aged 7-12  years
  • It presents more often in summer months when swimming is more common
  • It may be secondary to atopic dermatitis, trauma to the ear canal or discharging otitis media
  • The organisms involved include Staphylococcus aureusPseudomonas and fungi (e.g. Aspergillus). Candida is unusual.
 

Assessment

  • Key features include ear pain and discharge
  • No investigations are required

History

Common symptoms of otitis externa are:

  • Ear pain
  • Conductive hearing loss
  • Feeling of fullness (blockage) or pressure
  • Itchiness
  • +/- Discharge

Examination

  • The tragus and pinna are exquisitely tender when moved
  • The ear canal may be erythematous and dry, or it may have grey or black fungal plaques that resemble fuzzy cotton wool
  • Most commonly it is moist and oedematous, and the narrowed ear canal is filled with serous or purulent debris
  • Fungal infection is suggested by a “wet newspaper” appearance
  • Cerumen (ear wax) is characteristically absent
  • By definition, cranial nerve (CN) involvement (i.e. of the CN’s VII and IX-XII) is not associated with simple otitis externa
  • Inspect the ear for any foreign body

Investigations

Ear swabs are not required – they are unhelpful as the organisms grown on culture may or may not be true pathogens

Differential diagnoses

  • Otitis media with rupture of the tympanic membrane

Management

  • Analgesia is most important
  • Topical treatment is used rather than oral antibiotics

Initial management

Analgesia:

  • Oral paracetamol or ibuprofen
  • If a perforation of the tympanic membrane is unlikely (no discharge), a topical analgesia (e.g. Auralgan Otic) can be instilled.

Ear Toilet:

  • If a perforation of the tympanic membrane is unlikely, the ear can be irrigated with saline to remove debris.

Ear Drops:

  • Instil a combination antimicrobial/steroid ear drop (e.g. Sofradex, Otodex, Kenacomb)
  • If the ear canal is not too narrow to allow medication to flow freely, instil drops directly
  • If the ear canal is blocked, insert a dry ear wick and then instil drops down the wick every 6-8 hours. Review and replace wick in 48 hours.

Keep ear dry:

  • Soft wax earplugs should be used when showering
  • No swimming

Persisting infection which is thought to be fungal can be treated with Locacorten-Viaform ear drops, where as more severe cases may require a topical antifungal such as 1% clotrimazole.

Oral antibiotics are not used for treatment or prophylactically

Further management

  • Following treatment, prophylaxis with 2% acetic acid drops (e.g. Aqua-ear) should be instilled after swimming and showering. These drops can also be used to prevent recurrences.
  • The use of a blow dryer on a low setting after swimming to dry the ear canal has been suggested as a preventative measure. No studies have demonstrated the effectiveness of this suggestion.

Complications

  • Furunculosis of the externa ear is the development of a furuncle (boil) in the outer part of the ear canal and causes extreme pain. Management is with adequate analgesia and systemic (oral) antibiotics (flucloxacillin).
  • Cellulitis of the surrounding tissue requires similar treatment.

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