What is the treatment for myiasis (maggot infestation) in a wound?

Treatment of Maggots in Wounds (Myiasis)

The primary treatment for wound myiasis is immediate manual removal of all maggots, followed by thorough wound debridement, cleansing with sterile saline, and appropriate antibiotic therapy based on infection severity. 1

Initial Assessment and Management

1. Maggot Removal:

   • Use sterile forceps to manually extract all visible maggots 1
   • Irrigate wound thoroughly with sterile saline to flush out remaining larvae 1
   • Ensure complete removal of all larvae to prevent further tissue damage 1

2. Wound Debridement:

   • Perform sharp debridement to remove all necrotic tissue, slough, and foreign material 2
   • Trim any surrounding hyperkeratosis (callus) 2
   • Sharp debridement with scalpel, scissors, or tissue nippers is preferred over other techniques as it is more definitive and controllable 2

3. Wound Cleansing:

   • Irrigate with copious amounts of sterile saline or warm water 1
   • Avoid high-pressure irrigation as it may drive bacteria deeper into tissues 2
   • Chemical solutions like sodium hypochlorite (Dakin's solution) may be more effective for killing remaining larvae, though no solution achieves 100% mortality 3

Antibiotic Therapy

Select antibiotics based on infection severity:

1. Mild Infection (local inflammation limited to skin/subcutaneous tissue with ≤2 cm erythema):

   • Amoxicillin-clavulanate 1

2. Moderate Infection (cellulitis >2 cm or deeper extension):

   • Amoxicillin-clavulanate or ceftriaxone 1
   • Consider adding MRSA coverage if risk factors present 1

3. Severe Infection (systemic toxicity or metabolic instability):

   • Piperacillin-tazobactam plus vancomycin 2
   • Alternatively, carbapenems (imipenem, meropenem, ertapenem) 2

Ongoing Wound Care

1. Dressing Selection:

   • Use non-adherent contact layer as primary dressing 1
   • Apply absorbent foam dressing for exudate management 1
   • Consider antimicrobial dressings if signs of infection persist 1
   • Change dressings regularly based on exudate amount 1

2. Off-loading Pressure:

   • Essential for healing, especially in diabetic foot wounds 2
   • Use appropriate devices that permit easy wound inspection 2

3. Monitoring:

   • Inspect wound daily initially, then adjust frequency based on healing progress 2
   • Monitor for decrease in exudate, reduction in erythema, development of healthy granulation tissue, and resolution of systemic symptoms 1

Special Considerations

1. Vascular Assessment:

   • Mandatory for all chronic wounds 1
   • Prioritize revascularization when ischemia is present 1

2. Underlying Conditions:

   • Address factors such as diabetes control, nutritional status, and smoking 1
   • Optimize management of comorbidities to promote healing 1

3. Therapeutic vs. Wild Maggots:

   • Important distinction: While therapeutic maggots (Lucilia sericata) can be beneficial in controlled settings for wound debridement 4, 5, 6, 7, wild maggots in wounds represent an infection that requires immediate removal 1

Common Pitfalls to Avoid

1. Incomplete maggot removal - Ensure all larvae are removed to prevent continued tissue damage 1

2. Inadequate debridement - Thorough removal of all necrotic tissue is essential 2

3. Inappropriate antibiotic selection - Match antibiotic coverage to likely pathogens and infection severity 1

4. Failure to address underlying conditions - Particularly important in diabetic foot wounds 1

5. Neglecting pressure off-loading - Critical for healing, especially in weight-bearing areas 2

6. Delayed treatment - Prompt intervention is necessary to prevent further tissue damage and systemic infection 1

For wounds that fail to show improvement after 4 weeks of appropriate management, consider advanced wound therapies including negative-pressure wound therapy, oxygen therapies, or growth factors 1.