Clinical Features:
Frequently asymptomatic.  Gastrointestinal symptoms include abdominal pain and diarrhea.  Pulmonary symptoms (including Loeffler’s syndrome) can occur during pulmonary migration of the filariform larvae.  Dermatologic manifestations include urticarial rashes in the buttocks and waist areas.  Disseminated strongyloidiasis occurs in immunosuppressed patients, can present with abdominal pain, distension, shock, pulmonary and neurologic complications and septicemia, and is potentially fatal.  Blood eosinophilia is generally present during the acute and chronic stages, but may be absent with dissemination.

Laboratory Diagnosis:
Diagnosis rests on the microscopic identification of larvae (rhabditiform and occasionally filariform) in the stool or duodenal fluid.  Examination of serial samples may be necessary, and not always sufficient, because stool examination is relatively insensitive.
The stool can be examined in wet mounts:

• directly
• after concentration (formalin-ethyl acetate)
• after recovery of the larvae by the Baermann funnel technique
• after culture by the Harada-Mori filter paper technique
• after culture in agar plates

The duodenal fluid can be examined using techniques such as the Enterotest string or duodenal aspiration.  Larvae may be detected in sputum from patients with disseminated strongyloidiasis.

Diagnostic findings

• Microscopy
• Antibody detection
• Morphologic comparison with other intestinal parasites

Treatment:
The drug of choice for the treatment of uncomplicated strongyloidiasis is ivermectin with albendazole* as the alternative.  All patients who are at risk of disseminated strongyloidiasis should be treated.  For additional information, see the recommendations in The Medical Letter (Drugs for Parasitic Infections).

*This drug is approved by the FDA, but considered investigational for this purpose.