"There are three factors responsible for persistence of discharge from a chronic draining ear: Moisture, Opportunistic bacteria, Debris and diseased tissue"

James L Sheehy MD, 1966

The below protocol was last updated before 2013

Relevant Anatomy of the External Auditory Canal

• Squamous epithelium lined canal
• Cartilaginous portion (outer 1/3)
  • Site of cerumen production
  • Thicker skin
  • Fissures of Santorini: naturally occuring defects in the cartilaginous EAC that provides avenue of spread to superficial parotid lobe
• Bony portion (inner 2/3)
  • No sebaceous glands
  • Thin skin
  • Foramen of Huschke: incomplete ossification of anterior bony ear canal that produces an opening to the infratemporal region. This is a route for spread to deep lobe of parotid gland. 

Microbiology of Healthy External Auditory Canal

• >90% Gram positive organisms
  • Staph species (Staph auricularis, capitis, epidermidis)
  • Corynebacterium
  • Strep/Enterococci
• 4-5% Gram negative organisms
  • Pseudomonas, Moraxella, Proteus
• 2-3% Fungal isolates
• Slightly acidic environment (pH 6.1)

Diseases of the External Ear Canal

• Otitis Externa
  • ​Acute Otitis Externa: 3 elements for diagnosis
    • Rapid onset (48 hrs)
    • SYMPTOMS of ear canal inflammation (otalgia, itching, fullness, jaw pain, +/- hearing loss)
    • SIGNS of ear canal inflammation (tragal/pinna tenderness, ear canal edema, erythema, otorrhea)
    • 98% bacterial: (1) Pseudomonas (2) Staph aureus
    • Treatment: Topical therapy with quinolone ear drops. If no improvement in 48-72 hrs, look for other causes!
  • Chronic Otitis Externa
    • Look for underlying skin inflammation, signs of dermatitis, eczema
    • Underlying increased alkalinization (remember, healthy ear is slightly acidic)
    • Constant source of irritation (hearing aid users etc)
    • Prolonged use of aminoglycoside drops (neomycin) that can cause hypersensitivity reactions
    • Treatment: Address the underlying cause
• Otomycosis
  • ​Common Fungal organisms: Aspergillus, Candida species
  • Some thought that widespread use of ototopical ear drops is causative
  • Diagnosis: Hyphae can be seen on exam
  • Treatment: Debride intensely
    • Topical antifungals (Clotrimazole, Nystatin)
• Malignant Otitis Externa
  • ​Osteomyelitis involving the ear canal and surrounding bone (spread through fissures of santorini)
  • #1 most common organism, Pseudomonas. MRSA is second most common.
  • Association with immunocompromised state
  • Symptoms: Auricle proptosis, canal necrosis, granulation tissue at bony-cartilaginous junction, cranial nerve neuropathy, meningeal signs
  • Diagnosis: Technitium 99 scan
  • Treatment: Usually systemic antibiotics
• Foreign body
• Neoplasms
• Osteoradionecrosis