Acute Otitis Externa (Swimmers Ear)

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http://www.seattlechildrens.org/kids-health/parents/infections/bacterial...(otitis-externa)/

Otitis externa is an inflammation oaf the external ear canal and/or outer ear.  "Swimmers ear", as it is commonly called, can be precipitated by an alteration to  the skin of the external auditory canal.  While there is no relatonship between external otitis and middle ear pathology, these two diseae compose the most common cause of earachein children.   Under normal conditions, the skin of the ear is protected by waxy, water repellant secretions from sebaceous and apocrine glands.  However, when these normal barriers are lost, the skin becomes erythematous and macerated, allowing for invasion of exogenous organisms, most often bacterial or fungal.  Common causes of breakdown of this barrier, leading to otitis externa include: 

  1. Chronic moisture secondary to swimming or bathing
  2. Trauma from foreign bodies including  Q-tips and curretting to remove wax
  3. Dermatological conditions of the external canal
  4. Inadequate cerumen production that protects the external canal.
  5. Pruritius of the canal  leading  children to put their fingers or foreign bodies inside their ears to scratch.
  6. Wearing of hearing aids, earphones, and diving caps

 

Etiology

  1. Gram negative bacteria: Pseudomonas aeruginosa (50-65%), Proteus species, Kleibsiella, and Hemophilus, 30% are Polymicrobial
  2. Gram positive bacteria: Staphylococcus aureus and Streptococcus pyogenes
  3. Viruses: Herpes simplex and Herpes zoster
  4. Fungal: Candida species. Aspergillus

 

Clinical Manifestations

  1. Itching
  2. Purulent drainage from the canal
  3. Pain with manipulation of the pinna or tragus. The child will be very uncomfortable during otoscopic examination or will not allow you to look inside.
  4. There may be decreased hearing secondary to external canal swelling or presence of debris in the canal
  5. Enlarged postauricular and preauricular lymph nodes.
  6. On physical examination there will be swelling and redness of the external canal. Purulent material will be present and the tympanic membrane will be difficult to visualize

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Differential Diagnosis

  1. Ruptured tympanic membrane secondary to acute otitis media.  No  pain on manipulating the pinna or looking inside the canal. History consistent with AOM.
  2. Furuncle inside the canal. Will see on otoscopic examination.
  3. Child with tympanostomy tubes will often have drainage from the middle ear without pain.
  4. Malignant otisis externa with bone involvment is rare in kids.
  5. Psoriasis and contact dermatitis of the canal
  6. Rare carcinoma of the canal

 

Treatment

Clean out the canal, treat inflammation and infection, and pain control, 

  1. Antibiotic/steroid combination drops. Combination of Neomycin, Polymyxin B, and hydrocortisone is usually effective. The steroid will decrease swelling and inflammation. 
  2. May use chloroquinolone ear preparations if drum is not intact.
  3. May need to insert a wick to allow the drops to get into the canal. After insertion, soak the wick with the drops. May use rolled up tissue paper as a wick.
  4. Analgesics including codeine for extreme discomfort, NSAIDs
  5. Antifungals
  6. Burrow's solution-may help dry the skin of the canal.
  7. Heating pad
  8. Prophylaxis for swimmers
    1. ear plugs and bathing caps
    2. after swimming instillation of a solution of 1/2 vinegar and 1/2 isopropyl alcohol will help prevent infections.
  9. Rarely systemic antibiotics and ENT evaluation are necessary because topical therapy is ineffective. 
  10.  Immunocompromised hosts and diabetics may be difficult to treat
  11. May us hair dryer on low to dry canal

 

References

  1. Hughes Emma, and Lee Jeffrey Otitis Externa  Pediatrics in Review Vol. 22 No. 6 June 2001
  2. Clinical Practice Guidelines Acute Otitis Externa Otolaryngology-Head and Neck Surgery April 2006
  3. Stone K. Otitis Externa.  Pediatrics in Review Feb 2007
  4. Rosendield RM. Clinical Practice Guideline: Acute otitis externa. Otolaryngol Head Neck Surg April 2006

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