What are the differences in management and physical examination between otitis media and otitis externa?

Differences Between Otitis Media and Otitis Externa: Management and Physical Examination

The key difference between otitis media and otitis externa lies in their anatomical location, physical examination findings, and management approaches - otitis media affects the middle ear requiring systemic antibiotics in many cases, while otitis externa involves the ear canal and is primarily treated with topical preparations.

Diagnostic Features

Otitis Media

• Characterized by rapid onset of signs and symptoms of inflammation in the middle ear 1
• Physical examination reveals:
  • Bulging of the tympanic membrane 1
  • Limited or absent mobility of the tympanic membrane on pneumatic otoscopy 1
  • Air-fluid level behind the tympanic membrane 1
  • Distinct erythema of the tympanic membrane 1
• Tympanometry shows a flat tracing (type B) 1
• Common symptoms include otalgia, fever, irritability (especially in infants/toddlers), and sometimes otorrhea 1

Otitis Externa

• Involves inflammation of the external auditory canal 1
• Physical examination reveals:
  • Tenderness of the tragus (when pushed) and/or pinna (when pulled) - a hallmark sign 1
  • Diffuse ear canal edema and erythema 1
  • Normal tympanic membrane mobility on pneumatic otoscopy 1
  • Possible otorrhea or debris in the ear canal 1
• Tympanometry shows a normal peaked curve (type A) 1
• Common symptoms include otalgia (70%), itching (60%), fullness (22%), and possible hearing loss (32%) 1

Management Approaches

Otitis Media Management

• Pain assessment and management is essential 1
• For children 6 months to 2 years:
  • Antibiotic therapy is recommended for bilateral or unilateral AOM 1
  • High certainty of diagnosis is crucial for appropriate management 1
• For children ≥2 years:
  • Antibiotic therapy for severe symptoms (moderate to severe otalgia or fever ≥39°C) 1
  • Observation may be appropriate for non-severe cases with reliable follow-up 1
• First-line antibiotic: Amoxicillin (unless patient has taken amoxicillin in the last 30 days or has concurrent purulent conjunctivitis) 1
• Duration of therapy typically 10 days for children <2 years and 5-7 days for older children 1

Otitis Externa Management

• Pain assessment and management is essential 1
• Topical preparations are the mainstay of treatment for uncomplicated cases 1
• Systemic antibiotics should NOT be prescribed as initial therapy unless there is extension beyond the ear canal or specific host factors (diabetes, immunocompromised state) 1
• Aural toilet (cleaning) may be necessary to enhance drug delivery when the ear canal is obstructed 1
• Acidification with topical solutions (like 2% acetic acid with hydrocortisone) is effective in most cases 2
• For infected otitis externa, topical antibiotics such as ofloxacin otic solution 0.3% are indicated 3
• When tympanic membrane perforation is present or suspected, non-ototoxic topical preparations should be used 1

Key Differential Diagnostic Points

• Pneumatic otoscopy is crucial for differentiation:
  • Good tympanic membrane mobility suggests otitis externa 1
  • Limited or absent mobility suggests otitis media with effusion 1
• Location of pain/tenderness:
  • Otitis externa: Pain with manipulation of the tragus or pinna 1
  • Otitis media: Pain not typically exacerbated by ear manipulation 1
• Risk factors differ:
  • Otitis externa: Excessive moisture, trauma to ear canal, dermatologic conditions 1, 2
  • Otitis media: Upper respiratory infections, eustachian tube dysfunction 1

Common Pitfalls and Caveats

• Otitis externa can mimic the appearance of acute otitis media due to erythema involving the tympanic membrane - proper differentiation is essential 1
• Failure to adequately clean the ear canal can lead to misdiagnosis and inappropriate treatment 1, 2
• For otitis externa, avoid ear canal irrigation if the tympanic membrane integrity is uncertain 1
• For otitis media, inappropriate use of antibiotics for cases that could be managed with observation contributes to antibiotic resistance 1
• Reassessment is necessary if symptoms don't improve within 48-72 hours for both conditions 1
• Special attention should be paid to patients with diabetes or immunocompromised states who have otitis externa, as they are at risk for malignant (necrotizing) otitis externa 1, 4