Treatment of Suspected Strongyloides Infection
Ivermectin at a dose of 200 μg/kg orally for 2 consecutive days is the recommended first-line treatment for suspected strongyloidiasis, providing the highest cure rate with excellent tolerability. 1
Diagnostic Considerations
- Strongyloidiasis diagnosis is often challenging due to low sensitivity of stool examinations, with serological tests like ELISA being recommended as the primary diagnostic method 2
- Complete blood count should be obtained to identify eosinophilia, which is common in Strongyloides infections 2
- Clinical manifestations may include larva currens (an itchy, linear, urticarial rash that typically moves several millimeters per second around the trunk, upper legs, and buttocks) 3
- Pulmonary symptoms (Löeffler's syndrome) may occur due to larval migration through the lungs, presenting with fever, urticaria, wheezing, and dry cough 2
Treatment Regimens
Immunocompetent Patients
- Ivermectin 200 μg/kg orally for 2 consecutive days is the standard treatment 1, 4
- Dosing is weight-based according to FDA guidelines:
- 15-24 kg: 1 tablet (3 mg)
- 25-35 kg: 2 tablets
- 36-50 kg: 3 tablets
- 51-65 kg: 4 tablets
- 66-79 kg: 5 tablets
- ≥80 kg: 200 μg/kg 4
- Single-dose ivermectin (77% cure rate) is significantly more effective than albendazole (38% cure rate) 5
- A two-day course of ivermectin has shown superior efficacy (93-100% cure rate) compared to single-dose regimens 6, 7
Immunocompromised Patients
- Extended ivermectin regimen of 200 μg/kg on days 1,2,15, and 16 is recommended 1
- Immunocompromised patients may require repeated courses of therapy as cure may be difficult to achieve 4
- Suppressive therapy (once monthly ivermectin) may be helpful for controlling extra-intestinal strongyloidiasis in these patients 4
Important Considerations and Precautions
- Patients should take ivermectin tablets on an empty stomach with water 4
- Follow-up stool examinations should be performed to verify eradication of infection 4
- Persistent eosinophilia after treatment is associated with a high treatment failure rate (77%) and warrants reassessment 7
- Avoid initiating corticosteroid therapy without first treating strongyloidiasis, as this can precipitate potentially fatal hyperinfection syndrome 2, 1
- Patients with concomitant illnesses may benefit from the double-dose regimen of ivermectin rather than a single dose 6
Monitoring and Follow-up
- Monitor for symptoms of hyperinfection syndrome, including gastrointestinal bleeding, pneumonia, sepsis, or meningitis, particularly in immunocompromised patients 1
- Repeated stool examinations are necessary to document clearance of infection 4
- If treatment failure occurs, a second course of ivermectin should be administered 5
Alternative Treatment Options
- Albendazole 400 mg daily for 3 days is an alternative but less effective option, with cure rates of only 38-63% compared to ivermectin's 77-100% 3, 6, 5
- For cutaneous larva migrans, treatment options include ivermectin (200 mg/kg as a single dose) or albendazole (400 mg daily for 3 days) 3
Strongyloidiasis remains a potentially fatal parasitic infection, especially in immunocompromised hosts 8. Early diagnosis and appropriate treatment with ivermectin are essential to prevent progression to disseminated disease and hyperinfection syndrome.