What is the recommended treatment regimen for strongyloidiasis in adults and children, including ivermectin dosing, alternative therapies, and special considerations for immunocompromised patients, hyperinfection, disseminated disease, pregnancy, and follow‑up monitoring?

Treatment of Strongyloidiasis

First-Line Treatment Regimen

Ivermectin 200 mcg/kg orally for 2 consecutive days is the recommended treatment for uncomplicated strongyloidiasis, achieving cure rates of 83-100% with excellent tolerability. 1, 2, 3

• The FDA-approved dosing for strongyloidiasis is a single oral dose of 200 mcg/kg taken on an empty stomach with water 2
• However, the 2-day consecutive regimen (200 mcg/kg on days 1 and 2) achieves superior cure rates of 100% compared to 77% with single-dose treatment 3
• Taking ivermectin on an empty stomach increases bioavailability; a high-fat meal increases absorption by 2.5-fold but is not recommended per FDA labeling 2

Immunocompromised Patients (Critical Population)

For immunocompromised patients, administer ivermectin 200 mcg/kg on days 1,2,15, and 16 to prevent potentially fatal hyperinfection syndrome. 1, 4

• This extended regimen is essential for patients receiving corticosteroids, anti-TNF agents, calcineurin inhibitors, chemotherapy, or those with hematologic malignancies 1, 5
• Never initiate corticosteroid therapy without first treating strongyloidiasis, as this precipitates hyperinfection syndrome with mortality risk 1, 5
• Consider empiric treatment for patients from endemic areas who will receive immunosuppression, even without confirmed diagnosis 1

Alternative Therapy (When Ivermectin Unavailable)

• Albendazole 400 mg daily for 3 days is an alternative but significantly less effective option, with cure rates of only 38-63% 1, 6
• Thiabendazole 25 mg/kg twice daily for 3 days achieves 64-94% cure rates but causes frequent gastrointestinal side effects (16% incidence) including asthenia, epigastralgia, and disorientation 3

Hyperinfection and Disseminated Disease

Monitor for gastrointestinal bleeding, pneumonia, sepsis, or meningitis as warning signs of hyperinfection syndrome. 1

• In hyperinfection cases, continue ivermectin treatment beyond standard regimens until larvae clearance is documented 1
• Patients with HTLV-1 co-infection have significantly higher treatment failure rates (80% vs 29.2%) and may require additional treatment courses 7

Follow-Up Monitoring Protocol

Perform at least three stool examinations over 3 months following treatment to ensure eradication, as recrudescence can occur up to 106 days post-treatment. 2

• Use concentration techniques (Baermann apparatus) for stool examinations, as larval counts may be very low 2
• Conduct follow-up at 2 weeks, 1 month, 3 months, 6 months, 9 months, and 1 year after treatment 8
• If larvae reappear, retreatment with ivermectin is indicated 2
• Persistent eosinophilia after treatment correlates with treatment failure (77% non-cure rate) and warrants repeat stool examination 3

Special Populations

Pregnancy and Breastfeeding

• Ivermectin is classified as "human data suggest low risk" in pregnancy and is probably compatible with breastfeeding 4

Pediatric Patients

• Children under 10 years should not receive ivermectin for scabies (permethrin preferred), but ivermectin is used for strongyloidiasis in children ≥15 kg 4, 2
• Pediatric dosing follows the same weight-based protocol (200 mcg/kg) 2

Renal and Hepatic Impairment

• No dose adjustments required for renal impairment 4
• Safety of multiple doses in severe liver disease is not established 4

Critical Safety Warnings

Always exclude Loa loa co-infection before treating with ivermectin in anyone who has traveled to Central or West African endemic regions, as hypermicrofilaremia (>8,000 mf/mL) can cause fatal encephalitis. 4

• One study demonstrated increased mortality in elderly, debilitated patients receiving ivermectin, though not confirmed in subsequent reports 4
• Exclude onchocerciasis before treatment to avoid severe Mazzotti reactions 4

Common Pitfalls to Avoid

• Do not rely on single stool examination for diagnosis—serological ELISA testing has >80% sensitivity compared to poor stool microscopy sensitivity 5
• Do not use crude antigen ELISA tests—they have low sensitivity and specificity 5
• Do not assume cure without proper follow-up—autoinfection can persist despite initial negative stool samples 2
• Do not treat empirically without screening for Loa loa in travelers from endemic Africa—this can be fatal 4