Summertime brings many delightful activities that had been left hibernating during the cold winter months. With each activity, however, comes a variety of injuries and illnesses.  Certainly, we are aware of the potential injuries that come with activities like fireworks or skateboarding, but the summertime water activities bring their own unique issues like submersion injuries or C-spine injuries. Swimming can also lead to more minor, yet very annoying issues, like swimmer’s ear.  Let’s take a moment to enjoy a morsel of Otitis Externa:

Otitis Externa: Basics

• Acute Otitis Externa (AOE) is a diffuse inflammation of the external ear canal. [Rosenfeld, 2014]
• AOE may involve the pinna or the tympanic membrane.

• AOE is actually a cellulitis of the ear canal skin.
  • In North America, ~98% of acute otitis externa is due to bacterial infection.
  • Most common bacterial causes:
    • Pseudomonas aeruginosa 
    • Staphylococcus aureus 
    • Polymicrobial
  • Fungal infection is uncommon for acute otitis externa, but plays role in chronic otitis externa or in those who have been treated with antibiotics. [Rosenfeld, 2014]
  • The cellulitis can spread and lead to complications.

• Cause of otitis externa is multifactorial: [Rosenfeld, 2014]
  • Cerumen actually serves a purpose and efforts to remove it can increase risk of infection
  • Skin disorders may create additional debris in canal that supports infection
  • Local trauma to canal (often from cleaning attempts or hearing aids)
  • Exposure to moist environment (ex, humid summer climate or swimming)
    • Bacteria love to hang out in swimming pools and hot tubs!

Otitis Externa: Diagnosis

• AOE is uncommon in children <2 years of age. [Rosenfeld, 2014]

• Elements of the diagnosis include: [Rosenfeld, 2014]
  • Rapid onset (often within 48 hours) AND
    • Symptoms of ear canal inflammation:
      • Otalgia (often severe) (seen in ~70%)
      • Itching (seen in 60%)
      • Fullness  (seen in ~20%)
      • May also have hearing loss or jaw pain (worse with jaw movement)
    • Signs of ear canal inflammation:
      • Tenderness of the tragus or pinna or both OR
      • Diffuse ear canal edema or erythema or both
      • May have otorrhea, regional lymphadenitis, TM erythema, or even cellulitis of pinna and adjacent skin.
  • Tenderness of the tragus / pinna is often intense, even if visual inspection is underwhelming.

Otitis Externa: Ddx

• Acute otitis media w/ or w/o TM perforation
  • AOM and AOE may both lead to erythema of the TM.
    • Pneumatic otoscopy can differentiate – AOE will still have mobile TM.
  • AOM with perforation will lead to debris in canal and mimic AOE.
    • AOE will have very tender tragus and pinna while AOM w/ perforation often won’t.

• Malignant / Necrotizing otitis externa
  • Agressive infection
  • Predominantly affects patients with diabetes or other immunocompromised states
  • 90% due to Pseudomonas aeruginosa 
  • Can lead to skull base osteomyelitis and further invade local structures (like the brain).
  • Facial nerve paralysis may be early sign and is more commonly seen early in children vs adult. [Rubin, 1988]
  • Look for granulation tissue on the floor of the canal and at the bony-cartilaginous junction. [Rosenfeld, 2014]

• Cholesteatoma
  • Typically painless
  • Has alterations of the TM (ex, retraction, granulation tissue, perforation)
  • Need ENT referral for management

• Furunculosis (infected hair follicle on outer third of ear canal)
• Viral infections (ex, HSV – Ramsay Hunt syndrome)
• TMJ syndrome
• Skin disorders (ex, eczema, seborrhea, psoriasis) that involve the ear canal
• Contact allergy (ex, nickel allergy from jewelry)

Otitis Externa: Treatment

• Important to assess for factors that alter management strategies:
  • Perforated TM
  • PE tubes
  • Diabetes
  • Immunocompromised states (ex, HIV)
  • Prior radiation therapy

• Topical Antimicrobials are the main therapy!
  • Initial therapy for uncomplicated AOE is topical antibiotics. [Rosenfeld, 2014]
  • No clinical difference found between various options, although there is cost difference. [Rosenfeld, 2014]
  • Typical course is for at least 7 days.
  • If ear drops do not infuse easily, the patient may require a wick to be placed in the ear canal.
  • If there is a suspected perforated TM or known PE tubes, avoid ototoxic agents!
    • The middle ear does not have keratinized epithelium so drugs can pass through middle ear and into inner ear.
    • Can lead to hearing loss.
    • Need to avoid medicines with low pH, alcohol, aminoglycosides, or the combination drug neomycin/polymxinB/Hydrocortisone.
    • In US, only quinolone drops are approved for middle ear use.

• Avoid systemic antibiotics [Rosenfeld, 2014]
  • Oral antibiotics play no role in initial management of uncomplicated AOE.
  • If there is extension of cellulitis outside of the canal or concerning host factors, then systemic antibiotics are needed.
  • Malignant/necrotizing otitis externa requires systemic antibiotics and, possibly, anti-fungal medications in addition to surgical debridement.

• Do not forget analgesics!!
  • The periosteum is very sensitive.
  • NSAIDs to start with.
  • Low dose opiates may be appropriate.
    • Symptoms should improve within 48/72 hrs so prolonged courses of pain medications are not warranted.
  • Topical anesthetic drops:
    • May mask worsening disease, so great care should be taken if using them.
    • Should not be used if PE tube or TM perforation is present/suspected!

• Reassess in 48 – 72 hours
  • If no improvement in this timeframe, need to evaluate for other diagnoses.

References