Malignant (Necrotizing) Otitis Externa ent

Definition: An aggressive inflammatory condition of the external ear, spreading to the skull base.

Etiology & Risk Factors

• Causative Organism: Pseudomonas aeruginosa (Most common).
• Patient Profile:
  • Elderly.
  • Diabetics (Key risk factor).
  • Immunosuppressed patients.

Clinical Features

• Pain: Excruciating otalgia (hallmark sign).
• Otoscopy: Appearance of Granulations in the ear canal, typically at the Cartilaginous–Bony junction.
• Nerve Involvement:
  • Facial Paralysis: Common.
  • Skull Base Spread: May involve jugular foramen causing multiple cranial nerve palsies (IX, X, XI).

Spread of Infection

• Anteriorly: Temporomandibular fossa.
• Posteriorly: Mastoid.
• Medially: Middle ear and Petrous bone.

Diagnosis

Imaging Studies

Scan Type	Features & Utility
CT Scan	May show bony destruction (often not helpful early).
Gallium-67	Gold Standard for Monitoring. • Taken up by monocytes/macrophages. • Indicates soft tissue infection. • Can be repeated every 3 weeks to assess response.
Technetium-99	Reveals bone infection (Osteomyelitis). • Remains (+) for ~1 year. • Cannot be used to monitor disease resolution.

Treatment

1. General Measures

• Strict control of Diabetes.
• Aural Toilet: Removal of discharge, debris, granulations, and dead bone.

2. Antibiotic Therapy

Duration: Prolonged course (6–8 weeks or more).

Class	Drugs & Details
Quinolones (Oral)	Drug of Choice (Avoids admission). • Ciprofloxacin (750 mg OD). • Ofloxacin / Levofloxacin. • Can be combined with Rifampin.
IV Combo 1	Gentamicin + Ticarcillin. *Caution: Gentamicin is ototoxic/nephrotoxic.
IV Combo 2	3rd Gen Cephalosporin (Ceftriaxone/Ceftazidime) + Aminoglycoside.

3. Surgery

Prolonged antibiotic treatment has largely replaced radical surgery/resections for this condition.