What is the difference between otitis externa (swimmer's ear) and otitis media in terms of causes, symptoms, and treatment approaches?

Differences Between Otitis Externa (Swimmer's Ear) and Otitis Media

Otitis externa (swimmer's ear) is an infection or inflammation of the external ear canal requiring topical antibiotic treatment, while otitis media is an infection of the middle ear space typically requiring oral antibiotics. 1

Anatomical Location and Pathophysiology

• Otitis Externa:

  • Affects the external auditory canal
  • Often associated with excessive moisture and trauma that impair the canal's natural defenses 2
  • Commonly called "swimmer's ear" due to association with water exposure 3

• Otitis Media:

  • Affects the middle ear space (behind the tympanic membrane)
  • Often associated with eustachian tube dysfunction
  • May involve tympanostomy tubes in recurrent cases 4

Causes and Risk Factors

• Otitis Externa:

  • Primarily bacterial infection (Pseudomonas aeruginosa, Staphylococcus aureus, E. coli) 4
  • Less commonly fungal infection
  • Risk factors: swimming, humid environments, excessive sweating, ear canal trauma from cleaning 2, 3
  • Highest incidence in summer months and in southern regions 3

• Otitis Media:

  • Common pathogens include Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis 4
  • Risk factors: young age, winter season, upper respiratory infections

Clinical Presentation

• Otitis Externa:

  • Ear canal pain (often severe)
  • Pain with manipulation of tragus or pinna (hallmark sign) 5
  • Itching of ear canal
  • Discharge from ear canal
  • Erythema and swelling of the canal 2
  • Symptoms typically resolve within 6-7 days with proper treatment 5

• Otitis Media:

  • Ear pain (often less localized)
  • No pain with manipulation of external ear
  • Hearing loss
  • Fever (more common than with otitis externa)
  • Bulging or erythematous tympanic membrane on examination

Diagnostic Approach

• Otitis Externa:

  • Thorough cleansing of the ear canal is essential for diagnosis 2
  • Pain with tragus manipulation is diagnostic
  • Culture may be needed for recurrent or severe cases 1

• Otitis Media:

  • Visualization of the tympanic membrane is crucial
  • May require pneumatic otoscopy to assess membrane mobility
  • Tympanometry may be helpful in some cases

Treatment Approaches

Otitis Externa Treatment:

1. First-line therapy: Topical fluoroquinolone ear drops (e.g., ofloxacin 0.3%, ciprofloxacin 0.2%) 1, 4

   • For patients ≥13 years: Ten drops once daily for seven days
   • For pediatric patients (6 months to 13 years): Five drops once daily for seven days 4

2. Pain management: Acetaminophen or NSAIDs for immediate pain relief 1

3. Ear canal cleaning: Essential but avoid flushing 2

4. For fungal otitis externa: Azole antifungals (clotrimazole or miconazole) 1

5. For severe cases: Consider systemic antibiotics only if infection spreads beyond ear canal or in immunocompromised patients 6

Otitis Media Treatment:

1. First-line therapy: Oral antibiotics (typically amoxicillin) for 7-10 days 1

2. For patients with tympanostomy tubes: Topical antibiotic drops

   • Five drops twice daily for ten days in pediatric patients 4

3. Pain management: Similar approach with acetaminophen or NSAIDs

4. For chronic suppurative otitis media: Ten drops twice daily for fourteen days 4

Prevention Strategies

• Otitis Externa Prevention:

  • Keep ears dry (use alcohol-based ear-drying solutions after swimming) 3
  • Use ear plugs or swim caps during water activities 3
  • Avoid inserting cotton-tipped swabs into ear canal 1
  • Consider prophylactic acidifying solutions after water exposure 1, 2

• Otitis Media Prevention:

  • Pneumococcal vaccination
  • Influenza vaccination
  • Breastfeeding in infants
  • Avoid secondhand smoke exposure

Common Pitfalls and Caveats

1. Treatment errors to avoid:

   • Using neomycin-containing products as first-line therapy (can cause sensitization in 5-15% of patients) 1
   • Using oral antibiotics for uncomplicated otitis externa (leads to lower cure rates and more side effects) 1
   • Discontinuing treatment prematurely (complete the full course even if symptoms improve) 1
   • Using ear candles (no proven benefit and potential harm) 1

2. Special populations requiring extra attention:

   • Diabetic patients (higher risk for severe infections and necrotizing otitis externa) 1, 6
   • Immunocompromised patients (may need systemic therapy) 6
   • Patients with perforated tympanic membranes (avoid ototoxic medications) 5
   • Post-radiation patients (require delicate debridement) 1

3. When to refer to specialist:

   • Symptoms persisting beyond two weeks despite appropriate therapy 7
   • Signs of spreading infection beyond the ear canal
   • Suspicion of malignant (necrotizing) otitis externa
   • Recurrent episodes despite preventive measures