Is ultrasound a recommended primary method for skin management in an adult patient with a botfly infestation and no significant medical history, who has recently traveled to an endemic area?

Ultrasound for Botfly Myiasis: A Diagnostic Tool, Not a Treatment

Ultrasound is not a treatment method for botfly infestation but serves as a valuable diagnostic tool to confirm the presence of larvae before mechanical or surgical removal. 1, 2

Role of Ultrasound in Botfly Management

Ultrasound functions exclusively as a diagnostic modality in botfly myiasis and should be used when the clinical diagnosis is uncertain or to confirm larval viability before extraction. 2, 3

Specific Ultrasound Findings

• The "bubbling sign" is pathognomonic for live botfly larvae, demonstrating fluid circulation within the larva's respiratory system 3
• Ultrasound reveals a hypoechoic mass with a hyperechoic oblong-shaped core representing the larva, typically measuring 1-2 cm in length 3, 4
• Posterior acoustic spicules are visible, corresponding to the larva's cuticular spines that anchor it within the skin 4
• Real-time imaging can demonstrate larval movement, confirming viability 1, 2

When to Use Ultrasound

• Point-of-care ultrasound (POCUS) should be performed when furuncular lesions with central pores develop after travel to Central or South America, particularly if the patient reports sensation of movement 4
• Ultrasound is indicated when the clinical presentation mimics cellulitis, abscess, sebaceous cyst, or insect bite, preventing unnecessary antibiotic therapy or inappropriate incision and drainage 5, 4
• Use ultrasound to differentiate botfly myiasis from common soft tissue infections before proceeding with extraction 4

Actual Treatment Approach

Primary Management Strategy

• Mechanical or surgical extraction under local anesthesia is the definitive treatment for patients who desire removal 1, 4
• Make a small incision over the central pore, enlarge it sufficiently to grasp the larva with forceps, and extract it intact 4
• Punch biopsy technique can be used for simultaneous diagnosis and removal 1

Alternative to Active Treatment

• Observation without intervention is medically acceptable, as the larva will eventually emerge spontaneously after completing its development (typically 5-10 weeks total) 1
• This option should be discussed through shared decision-making, weighing patient anxiety, risk of secondary infection, and cosmetic concerns against the self-limited nature of the infestation 1

Post-Extraction Care

• Clean the wound with sterile saline, apply a non-adherent dressing, and prescribe prophylactic antibiotics to prevent secondary bacterial infection 4
• Suture the extraction site if necessary and provide standard wound care instructions 4

Critical Diagnostic Pitfalls

• Do not misdiagnose as bacterial abscess and treat with antibiotics alone, as this will not resolve the infestation 5, 4
• Do not perform incision and drainage without confirming the diagnosis, as incomplete larval removal can lead to retained foreign body and inflammatory reaction 4
• Look for the central punctum (breathing pore) and history of travel to endemic areas (Central/South America) or outdoor activities near rodent burrows in North America (Cuterebra species) 5, 4
• Serosanguinous discharge from the central pore and patient-reported sensation of movement are highly specific clinical clues 1, 3