Otitis externa

Disclaimer

These guidelines have been produced to guide clinical decision making for the medical, nursing and allied health staff of Perth Children’s Hospital. They are not strict protocols, and they do not replace the judgement of a senior clinician. Clinical common-sense should be applied at all times. These clinical guidelines should never be relied on as a substitute for proper assessment with respect to the particular circumstances of each case and the needs of each patient. Clinicians should also consider the local skill level available and their local area policies before following any guideline. 

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Aim 

To guide PCH ED staff with the assessment and management of otitis externa in children who present to the Emergency Department.

Definition

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 aureus Pseudomonas 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 blowdryer 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.

Bibliography

  1. Clarke RC. Pediatric OtolaryngologyPractical Clinical Management. July 2017
  2. Fleisher GR, Ludwig S. Textbook of Pediatric Emergency Medicine. 6th ed. Philadelphia: Lippincott Williams & Wilkins, 2010.
  3. Pediatric Otolaryngology for the Clinician By: Ron B. Mitchell (Editor), Kevin D. Pereira (Editor) 2010

Endorsed by:  Director, Emergency Department   Date:  Mar 2018


 Review date:   Mar 2021


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