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.
- First-line chronic Strongyloides assessment uses serology plus sensitive repeated stool testing such as concentration, Baermann, agar culture or PCR; ordinary single microscopy has poor sensitivity.
- Hyperinfection diagnosis depends on abundant larvae in stool, sputum or other fluids, but treatment must not wait when epidemiology and critical illness are compelling.
- Ivermectin 200 micrograms/kg orally once daily for one to two days is the treatment of choice for uncomplicated chronic strongyloidiasis under a specialist plan.
- For hyperinfection, give ivermectin 200 micrograms/kg once daily until stool and sputum remain negative for two weeks; non-oral routes require specialist regulatory access.
- Ascaris and Trichuris eggs are ingested from faecally contaminated soil or food; hookworm larvae penetrate skin and chronic blood feeding causes iron deficiency.
- UK-licensed mebendazole treatment for ascariasis, trichuriasis and hookworm is 100 mg orally twice daily for three consecutive days in adults and children over two years.
- Prevention combines footwear, sanitation, hand and food hygiene and population deworming in endemic programmes; individual UK travellers do not take routine prophylactic anthelmintics.
Key red flags
Corticosteroids can precipitate fatal Strongyloides hyperinfection even decades after exposure; assess risk before the first dose whenever the clinical situation permits.
Eosinophilia may disappear during hyperinfection, so a normal count in an immunosuppressed deteriorating patient is not reassuring.
Unexplained Gram-negative bacteraemia, meningitis or polymicrobial sepsis with pulmonary or gastrointestinal symptoms should prompt an urgent search for disseminated larvae.
Ileus, gastrointestinal bleeding, hypoxaemia, diffuse infiltrates or respiratory failure indicates high-burden Strongyloides disease requiring inpatient daily treatment.
Severe abdominal pain, vomiting and obstruction can follow a heavy Ascaris burden; biliary migration may cause cholangitis or pancreatitis.
Profound iron-deficiency anaemia, rectal prolapse or growth and nutritional impairment suggests heavy hookworm or Trichuris infection and needs complication care as well as deworming.
Cough, wheeze, hypoxaemia, haemoptysis and diffuse pulmonary infiltrates in an immunosuppressed host can represent massive accelerated larval migration.
Enteric bacteria carried across damaged bowel produce Gram-negative bacteraemia, polymicrobial infection or meningitis and contribute heavily to mortality.
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.
- If urgent high-dose steroids cannot wait and exposure risk is material, discuss empirical ivermectin with infection specialists while samples are obtained.
- Assess Loa loa exposure, pregnancy, weight and medicine access before ivermectin; define how cure or suppression will be confirmed during immune therapy.