Synopsis
Detect lifelong Strongyloides infection before immunosuppression, treat hyperinfection as an emergency, and diagnose and manage Ascaris, hookworm and Trichuris disease using species-specific risks.
- Strongyloides larvae penetrate skin, migrate through lungs and mature in small bowel; internal autoinfection allows untreated infection to persist for life.
- Chronic disease may be silent or cause abdominal pain, diarrhoea, urticaria, wheeze and rapidly moving serpiginous larva currens, often with intermittent eosinophilia.
- Before substantial steroids, biologics, chemotherapy, transplantation or HTLV-1-associated immune change, screen anyone with plausible tropical or subtropical soil exposure.
Key red flags
Corticosteroids can precipitate fatal Strongyloides hyperinfection even decades after exposure; assess risk before the first dose whenever the clinical situation permits.
Cough, wheeze, hypoxaemia, haemoptysis and diffuse pulmonary infiltrates in an immunosuppressed host can represent massive accelerated larval migration.
Investigation priorities
Identify eosinophilia, anaemia and epidemiological risk while judging urgency.
Management branches
Steroids, biologics, chemotherapy or transplantation are planned in someone with plausible endemic soil exposure.
- Take a lifetime country and rural-soil history rather than limiting questions to recent travel, and inspect for larva currens or unexplained gastrointestinal symptoms.
- Request Strongyloides serology and sensitive repeated stool testing where time allows; document eosinophils but do not use a normal count to end assessment.
Key medicines
Ivermectin for uncomplicated strongyloidiasisGive 200 micrograms/kg orally once daily for one to two consecutive days, with extension or repeat dosing defined by immune status, response and specialist follow-up.
Ivermectin for hyperinfectionGive 200 micrograms/kg once daily and continue until the patient improves and stool and sputum remain negative for larvae for at least 14 consecutive days.