Otitis Externa

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Introduction & Etiopathogenesis - Ear Canal Calamity

  • Otitis Externa (OE): Inflammation or infection of the external auditory canal (EAC); acute diffuse type often called "Swimmer's Ear".
  • Etiology:
    • Bacterial (Most Common): Pseudomonas aeruginosa (predominant), Staphylococcus aureus.
    • Fungal (Otomycosis): Aspergillus spp. (e.g., A. niger - black spores), Candida spp.
    • Non-infectious: Eczematous, seborrheic dermatitis, contact sensitivity.
  • Pathogenesis:
    • Breakdown of protective skin-cerumen barrier & loss of acidic pH in EAC.
    • Predisposing Factors: Moisture (swimming, humidity), trauma (e.g., cotton swabs, scratching), alkaline soaps, ↓cerumen.
    • Leads to canal skin inflammation, edema, erythema, severe otalgia, and otorrhoea. Swimmer's Ear (Otitis Externa) Diagram

Pseudomonas aeruginosa is the predominant pathogen in up to 70% of acute diffuse otitis externa cases, thriving in moist environments.

Clinical Picture & Diagnosis - Itchy, Ouchy Ears

  • Symptoms:
    • Severe otalgia: ↑ with tragal/pinna movement.
    • Pruritus: Esp. fungal (otomycosis).
    • Otorrhea: Scanty, watery/purulent.
    • Conductive hearing loss: Due to canal edema/debris.
    • Aural fullness.
  • Signs (Otoscopy):
    • Tragal tenderness: Key sign.
    • Pinna tenderness.
    • External Auditory Canal (EAC): Edema, erythema.
    • Debris in EAC:
      • Bacterial: Wet, "blotting paper" appearance.
      • Fungal: Fluffy, white/black/yellow dots (Aspergillus/Candida).
    • Tympanic Membrane (TM): Usually mobile, may be obscured.
  • Diagnosis: Primarily clinical. Swab for culture & sensitivity (C&S) if refractory/recurrent.

⭐ Tenderness on tragal pressure or pulling the pinna is a hallmark sign of otitis externa.

OE Variants & Red Flags - Ear's Wild Side

  • Malignant (Necrotizing) OE (MOE):
    • Pseudomonas aeruginosa in elderly diabetics/immunocompromised.
    • Severe nocturnal otalgia, purulent discharge.
    • Key: Granulation tissue at bony-cartilaginous junction.
    • ⚠️ CN VII palsy common; others (IX-XII) possible.
    • Dx: CT/MRI (bone erosion), biopsy crucial.
    • Tx: IV antipseudomonals (e.g., Ciprofloxacin 6-8 wks), surgical debridement. Malignant Otitis Externa in Diabetic Patient
  • Fungal OE (Otomycosis):
    • Aspergillus spp. (black/grey spores, "wet newspaper" look).
    • Candida spp. (white/creamy hyphae, "cottage cheese" look).
    • Intense itching (pruritus), visible fungal debris.
    • Tx: Thorough aural toilet, topical antifungals (e.g., Clotrimazole).
  • Eczematous OE:
    • Chronic itching, scaling, erythema. Often bilateral.
    • Associated with dermatitis/psoriasis. Tx: Topical steroids.
  • General Red Flags (⚠️ Refer Urgently):
    • Severe pain disproportionate to findings.
    • Cranial nerve deficits (esp. facial nerve).
    • Immunocompromised status (Diabetes, HIV).
    • No improvement in 48-72 hrs with topical Rx.
    • Cellulitis spreading beyond External Auditory Canal (EAC).

⭐ Granulation tissue at the bony-cartilaginous junction of the External Auditory Canal in an elderly diabetic patient is a hallmark of Malignant Otitis Externa (Necrotizing Otitis Externa).

Management & Prevention - Soothing the Swimmer's Ear

📌 Mnemonic: CLEANSE

  • Cleaning (Aural Toilet): Gentle suction/dry mopping. Essential first step.
  • Local Therapy (Topical):
    • Antibiotic drops: Fluoroquinolones (ciprofloxacin, ofloxacin) preferred.
    • Add corticosteroids (dexamethasone) to reduce inflammation.
    • Acidifying agents (e.g., 2% acetic acid) restore canal pH.
  • Ear Wick: Use if canal edema obstructs drop delivery.
  • Analgesia: Systemic NSAIDs (ibuprofen, paracetamol) for pain relief.
  • No Water / Systemic Antibiotics:
    • Keep ear dry (crucial for healing).
    • Systemic oral fluoroquinolones for severe infection (cellulitis), immunocompromised, or failed topical treatment.

⭐ Topical fluoroquinolones (e.g., ciprofloxacin) are preferred over aminoglycosides if tympanic membrane integrity is uncertain, due to lower ototoxicity risk.

Prevention Strategies (Education - the final 'E' of CLEANSE):

  • Keep ear canal dry: Use earplugs (swimming), thorough drying post-water.
  • Avoid ear trauma: No cotton swabs, avoid scratching canal.
  • Prophylactic drops: Acetic acid 2% or alcohol-based solutions after water exposure.

Otitis Externa Management: Evidence-Based Statements

High-Yield Points - ⚡ Biggest Takeaways

  • Most common cause: Pseudomonas aeruginosa.
  • Key symptom: Severe otalgia exacerbated by tragal pressure or pinna movement.
  • Malignant Otitis Externa: Aggressive infection in diabetics/immunocompromised; Pseudomonas implicated; can cause facial palsy and skull base osteomyelitis.
  • Otomycosis: Fungal infection (e.g., Aspergillus, Candida); intense itching is characteristic.
  • Treatment: Aural toilet, topical antibiotics +/- steroids. Systemic for severe cases.
  • Prevention: Keep ears dry; avoid trauma (e.g., cotton swabs).

Practice Questions: Otitis Externa

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Which of the following drugs can cause ototoxicity?

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Flashcards: Otitis Externa

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Otitis externa hemorrhagica can also be caused by both _____ and mycoplasma, in addition to S. pneumo

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Otitis externa hemorrhagica can also be caused by both _____ and mycoplasma, in addition to S. pneumo

influenza

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