Symptoms of Strongyloidiasis
Strongyloidiasis presents with a wide spectrum of clinical manifestations ranging from completely asymptomatic infection to life-threatening disseminated disease, with the most common symptoms being itchy urticarial rash, abdominal pain, bloating, wheeze, dry cough, and in severe cases, gram-negative bacteremia and respiratory failure. 1
Clinical Presentation by Disease Severity
Uncomplicated/Chronic Infection
The majority of strongyloidiasis cases are asymptomatic or present with mild, nonspecific symptoms 1:
- Gastrointestinal symptoms: Abdominal pain, bloating, diarrhea 1
- Dermatologic manifestations:
- Respiratory symptoms: Wheeze, dry cough (from larval migration through lungs) 1
- Eosinophilia: Often present but not invariable 1
Loeffler's Syndrome (Acute Larval Migration)
When larvae migrate through the lungs 1-2 weeks after infection 1:
- Fever
- Urticaria
- Wheeze
- Dry cough
- Rarely hemoptysis
- Migratory pulmonary infiltrates on chest radiograph 1
Hyperinfection Syndrome
This is a medical emergency occurring in immunocompromised patients (particularly those on corticosteroids, with HTLV-1, or immunosuppression) 2, 3:
- Respiratory manifestations: Cough, breathlessness, hemoptysis, bilateral pneumonia, respiratory failure requiring mechanical ventilation 1, 2
- Gastrointestinal complications:
- Systemic manifestations:
Uncommon Presentations
Gastric Outlet Obstruction
Rare presentation with 5:
- Non-projectile vomiting
- Epigastric pain
- Indigestion
- Anorexia
- Significant weight loss
- Can endoscopically mimic malignancy with circumferential ulcerated duodenal lesions
Protein-Losing Enteropathy
Particularly in immunocompromised patients 6:
- Weight loss
- Vomiting
- Diarrhea
- Hypoalbuminemia
- Elevated IgE levels
Critical Clinical Pitfalls
The most dangerous pitfall is initiating corticosteroid therapy without first excluding strongyloidiasis, as steroids can trigger fatal hyperinfection syndrome 1. The guidelines explicitly state: "Concurrent strongyloidiasis infection should be excluded where this is the case" before prolonged/high-dose steroid courses 1.
Eosinophilia may be absent in severe disease or hyperinfection, making diagnosis more challenging 5, 2. Normal eosinophil counts do not exclude strongyloidiasis.
Stool microscopy has low sensitivity for Strongyloides detection 1, so negative stool examination does not rule out infection—serology and histopathology may be required 5, 6.
The incubation period can be extraordinarily long—symptoms may appear up to 25 years after initial infection due to the parasite's unique autoinfection capability 1, making travel history from decades prior clinically relevant.