What is the most likely diagnosis and recommended treatment for a patient presenting with painful external ear on palpation?

Acute Otitis Externa (Swimmer's Ear)

The most likely diagnosis is acute otitis externa, and the recommended treatment is topical fluoroquinolone ear drops (ofloxacin 0.3% or ciprofloxacin 0.2%) combined with appropriate oral analgesics for pain control. 1, 2

Diagnostic Confirmation

Intense tenderness when touching the tragus or pinna is the hallmark sign of acute otitis externa and is often disproportionate to what you see on visual inspection. 1 This distinguishes it from middle ear infections (otitis media), where tragal tenderness is absent. 3

Additional diagnostic criteria include: 1

• Rapid onset of symptoms (typically within 48 hours) occurring in the past 3 weeks
• Ear canal inflammation signs: edema, erythema, or discharge
• Symptoms: severe ear pain, itching, fullness, or hearing loss

The condition is caused by bacterial infection in 98% of cases, with Pseudomonas aeruginosa (20-60%) and Staphylococcus aureus (10-70%) as the primary pathogens. 1, 4

Essential First Step: Aural Toilet

Before applying any medication, you must clear the ear canal of debris, cerumen, and inflammatory material using gentle suction, dry mopping, or irrigation with body-temperature water. 2 This step is critical because medication cannot penetrate through debris to reach infected tissue. 2 Only 40% of patients self-administer drops correctly when this step is skipped. 2

First-Line Treatment: Topical Antimicrobials

Topical antibiotic ear drops are the definitive first-line treatment—NOT oral antibiotics. 1, 2 Topical therapy achieves clinical cure rates of 65-90% within 7-10 days and delivers drug concentrations 100-1000 times higher than oral antibiotics. 2, 5

When tympanic membrane integrity is uncertain:

• Use ONLY non-ototoxic fluoroquinolones: ofloxacin 0.3% or ciprofloxacin 0.2% 1, 2, 5
• Avoid aminoglycoside-containing drops (neomycin/polymyxin B) due to ototoxicity risk 1, 2

When tympanic membrane is confirmed intact:

• Any FDA-approved topical preparation is acceptable (fluoroquinolones, neomycin/polymyxin B/hydrocortisone, or acetic acid 2%) 2, 6
• No single agent is clinically superior to another 2, 4, 6

Treatment duration:

• Prescribe for minimum 7 days even if symptoms resolve earlier 2
• Continue up to 14 days maximum if symptoms persist 2

Pain Management (Critical Component)

Pain assessment and aggressive analgesia are essential because otitis externa pain is often severe and disproportionate to visual findings. 1, 3, 7

• Mild-to-moderate pain: Acetaminophen 650-1000 mg every 6 hours OR ibuprofen 400-600 mg every 6 hours 2, 7
• Severe pain: Short-term opioid-containing analgesics for the first 48-72 hours 2, 3, 7
• Pain typically improves within 48-72 hours of starting topical therapy 1, 2, 3, 8

Proper Drop Administration Technique

Instruct patients to: 2

• Warm the bottle in hands for 1-2 minutes to prevent dizziness
• Lie with affected ear upward
• Fill the ear canal completely with drops
• Remain in this position for 3-5 minutes (use a timer)
• Apply gentle tragal pumping or pinna movement to eliminate trapped air
• Have someone else administer drops when possible (improves adherence significantly)

When Oral Antibiotics ARE Indicated

Reserve systemic antibiotics for these specific situations ONLY: 1, 2, 7

• Extension of infection beyond the ear canal (periauricular cellulitis or swelling)
• Diabetes mellitus or immunocompromised status
• Severe canal edema preventing adequate topical drug delivery despite wick placement
• Failure to improve after 48-72 hours of appropriate topical therapy

When indicated, prescribe oral fluoroquinolones (ciprofloxacin 500 mg twice daily) to cover P. aeruginosa and S. aureus. 2, 7

Reassessment Criteria

Reassess within 48-72 hours if no improvement occurs. 2, 8 Common reasons for treatment failure include: 2

• Inadequate drug delivery due to canal obstruction or poor adherence
• Allergic contact dermatitis from topical agents (especially neomycin, which causes reactions in 13-30% of patients with chronic otitis externa)
• Fungal co-infection (otomycosis)
• Incorrect diagnosis (chronic suppurative otitis media, necrotizing otitis externa)

Critical Pitfalls to Avoid

• Prescribing oral antibiotics for uncomplicated cases (occurs inappropriately in 20-40% of patients; topical therapy achieves 77-96% cure rates versus only 30-67% for oral antibiotics) 2, 4
• Using ototoxic preparations when tympanic membrane integrity is uncertain 1, 2
• Skipping aural toilet before drop administration 2
• Inadequate pain management 2, 3
• Irrigating the ear canal in diabetic or immunocompromised patients (can precipitate necrotizing otitis externa) 2

Patient Education

• Keep the ear dry during treatment (use petroleum jelly-coated cotton or earplug before showering) 2
• Avoid swimming and water exposure until infection resolves 2, 9
• Do NOT insert cotton swabs or any objects into the ear canal 2, 9
• Complete the full 7-day course even if symptoms improve earlier 2
• Return if symptoms don't improve within 48-72 hours or persist beyond 2 weeks 2