How should ear or nasal myiasis be diagnosed and managed?

Management of Ear and Nasal Myiasis

For ear or nasal myiasis, the primary treatment is mechanical removal of all visible larvae using direct visualization (otoscopy/endoscopy) combined with manual extraction, followed by ivermectin irrigation to expel remaining larvae, plus systemic ivermectin to prevent recurrence.

Diagnosis

Clinical Presentation

• Nasal myiasis typically presents with nasal congestion, purulent discharge, sensation of movement in the nose, epistaxis, and foul odor 1, 2
• Otic myiasis presents with ear pain, discharge, sensation of movement, hearing loss, and may be associated with chronic otitis media or previous ear surgery 3
• Patients may report seeing larvae in discharge or feeling movement in affected cavities 1, 3

Diagnostic Approach

• Direct visualization is essential: Use nasal endoscopy (rigid or fiberoptic) for nasal myiasis to identify larvae and assess extent of tissue involvement 2
• For otic myiasis, perform otoscopy or otomicroscopy to visualize larvae in the ear canal 3
• Obtain imaging (CT scan) if extensive tissue destruction is suspected or to assess sinus involvement 1
• Identify predisposing factors: chronic otitis media, previous ear surgery, mental deficit, poor hygiene, outdoor sleeping, malnutrition, or underlying conditions like leishmaniasis 1, 3

Treatment Protocol

Immediate Mechanical Removal

• First-line approach: Manual extraction of visible larvae using toothed forceps under direct visualization (endoscopy for nasal, otoscopy for otic) 1, 2
• Remove all accessible larvae during initial examination 2

Ivermectin Irrigation (Critical Step)

• If manual extraction is incomplete or unsuccessful, perform irrigation with ivermectin solution directly into the affected cavity 1
• This typically results in self-expulsion of remaining larvae within 15 minutes 1
• This approach is particularly effective for larvae embedded in tissue or inaccessible to forceps 1

Systemic Therapy

• Administer oral ivermectin as adjunctive therapy to kill any remaining larvae and prevent recurrence 1
• Continue treatment until all larvae are expelled and symptoms resolve 1

Post-Treatment Verification

• Perform follow-up endoscopy/otoscopy to confirm complete larval removal 2
• Obtain imaging (CT) if initial presentation showed extensive involvement, to document resolution 1

Management of Underlying Conditions

• Treat any predisposing factors: chronic otitis media, open wounds, or underlying infections 3
• Screen for conditions like leishmaniasis if nasal tissue destruction is present 1
• Address hygiene and environmental factors to prevent recurrence 3

Critical Pitfalls to Avoid

• Never use ototoxic ear drops (aminoglycosides) if tympanic membrane integrity is uncertain, as they cause permanent sensorineural hearing loss 4
• Do not attempt ear irrigation if tympanic membrane perforation is suspected 4
• Do not rely solely on manual extraction—ivermectin irrigation is often necessary for complete removal 1
• Ensure complete larval removal, as retained larvae can cause ongoing tissue destruction and secondary infection 3