What is the recommended treatment for a patient suspected of having Strongyloides infection, especially if they have a history of travel to tropical and subtropical regions or have a weakened immune system?

Treatment of Strongyloides Infection

For patients with suspected or confirmed Strongyloides infection, treat with ivermectin 200 μg/kg orally for 2 consecutive days, which provides cure rates of 77-100% with excellent tolerability. 1, 2, 3

Standard Treatment Regimen

• Ivermectin 200 μg/kg orally for 2 consecutive days is the first-line treatment for uncomplicated strongyloidiasis in immunocompetent patients 1, 2, 3
• Take on an empty stomach with water to optimize absorption 3
• Albendazole 400 mg daily for 3 days is an alternative but significantly less effective option, with cure rates of only 38-63% compared to ivermectin's 77-100% 2

Immunocompromised Patients: Critical Modification Required

For immunocompromised patients, use an extended regimen: ivermectin 200 μg/kg on days 1,2,15, and 16. 1, 2

• This includes patients on corticosteroids, anti-TNF therapy, calcineurin inhibitors, chemotherapy, or those with HTLV-1 infection or hematologic malignancies 4
• Multiple treatment courses at 2-week intervals may be required, and cure may not be achievable in severely immunocompromised hosts 3
• Suppressive therapy (once monthly) may be necessary for control of extra-intestinal strongyloidiasis 3

Pre-Treatment Screening: Mandatory in High-Risk Scenarios

Before initiating any immunosuppressive therapy (especially corticosteroids), screen patients from endemic tropical/subtropical regions for Strongyloides and treat empirically if testing is unavailable. 2, 4

• Endemic regions include most of Africa, Central and South America, Southeast Asia, Middle East, former Soviet Union states, and rural Appalachian regions of the southern United States 4
• Long-term travelers (>1 month) to endemic areas warrant screening even years after exposure due to the parasite's ability to persist indefinitely through autoinfection 4, 5
• Critical pitfall to avoid: Never initiate corticosteroids without Strongyloides assessment, as this can precipitate potentially fatal hyperinfection syndrome 2, 4

Loa loa Co-Infection: Essential Pre-Treatment Assessment

In patients with significant exposure to West or Central Africa, exclude Loa loa infection BEFORE treating with ivermectin. 1, 3

• Co-infection with Loa loa can cause serious or fatal encephalopathy following ivermectin treatment 3
• Symptoms include confusion, lethargy, stupor, seizures, coma, neck/back pain, conjunctival hemorrhage, and urinary/fecal incontinence 3
• Implement careful post-treatment follow-up in these patients 3

Diagnostic Approach for Suspected Cases

• Serology (ELISA with recombinant antigens) is the primary diagnostic method, with sensitivity exceeding 80% 4, 5
• Stool microscopy has poor sensitivity for Strongyloides; at least 3 concentrated stool samples are needed, though sensitivity remains limited 4, 5
• Many experts recommend treating seropositive patients despite negative stool examinations 4
• Eosinophilia may be absent during hyperinfection syndrome, so do not rely on it for diagnosis 4

Post-Treatment Monitoring

• Repeat stool examinations are necessary to document clearance of infection 3
• Serology and eosinophil count should be monitored, with significant reductions expected at approximately 96 days and 270 days respectively after successful treatment 6
• For empirical treatment of asymptomatic eosinophilia, repeat treatment at 8 weeks to treat any residual worms once they have developed into adults 1

Clinical Presentations Requiring Immediate Treatment

• Larva currens: itchy, linear, urticarial rash moving several millimeters per second around trunk, upper legs, and buttocks 2
• Löffler's syndrome: fever, urticaria, wheeze, dry cough occurring 1-2 weeks after infection due to larval lung migration 1, 5
• Hyperinfection syndrome: gastrointestinal bleeding, pneumonia, sepsis, meningitis, or unexplained gram-negative bacteremia in immunosuppressed patients 2, 4

Special Populations

• Pregnancy: Ivermectin is Category C and should not be used during pregnancy; safety has not been established 3
• Lactation: Ivermectin is excreted in breast milk; treatment should only be undertaken when risk of delayed treatment outweighs possible risk to newborn 3
• Pediatric: Safety not established in children weighing less than 15 kg 3