Myiasis

Background

Myiasis in patient neck

• Caused by Diptera species. Dermatobia hominis (botfly) is most common cause in North America
• Cutaneous (includes follicular, wound, and migratory) type is most common
  • Can also occur in mouth, urogenital, ophthalmic, nasopharyngeal location
• Typically occurs in tropical and subtropical areas. US cases typically due to travel to endemic region
• Sensation of movement within lesion
• Serous drainage

Differential Diagnosis

Travel-related skin conditions

• Papules
  • Insect bites
  • Scabies
  • Seabather's eruption
  • Cercarial dermatitis (Swimmer's Itch)
• Macular
  • Chikungunya
• Sub Q Swelling and Nodules
  • Myiasis
  • Tungiasis
  • Loa loa
  • African Trypanosomiasis
  • Onchocerciasis
• Ulcers
  • Tropical pyoderma
  • Leishmaniasis
  • Mycobacterium marinum
  • Buruli ulcer
  • Dracunculiasis (Guinea Worm disease)
• Linear and Migratory Lesions
  • Cutaneous larvae migrans
  • Photodermatitis

See also domestic U.S. ectoparasites

Domestic U.S. Ectoparasites

• Bed bugs
• Lice
• Scabies (Mites)
• Ticks
• Fleas
• Pseudoparasites
• Delusional parasitosis (Ekbom syndrome)

See also travel-related skin conditions

Evaluation

• Clinical diagnosis

Management

If entire larvae is not removed, severe inflammatory response occurs

• Occlusion of central pore with petroleum jelly or mineral oil interrupts oxygen supply and causes larvae to migrate to surface where it can be grasped with forceps and removed
  • Can take up to 24 hours
• Manual removal by squeezing out larvae
• Surgical removal by making incision over larvae and removing with forceps
• Ivermectin - single PO dose or topical application
• Wound myiasis requires surgical debridement
• Ocular, nasopharyngeal, urogenital myiasis should prompt appropriate specialist consultation for management

Disposition

• Cutaneous myiasis generally may be discharged after removal
• Disposition of other forms based on discussion with specialist

See Also

• Parasitic Diseases
• Travel Medicine