Rapid development of migratory, linear, and serpiginous lesions in association with immunosuppression

Key teaching points • Strongyloides is a genus of obligate gastrointestinal nematodes (roundworms) of vertebrates. The species stercoralis , the usual cause of human infection, has the potential for autoinfection and multiplication in human beings. • Peripheral eosinophilia without a known cause may represent chronic, persistent infection with Strongyloides stercoralis. • Undiagnosed disease is prevalent, especially among immigrants and military veterans who served in highly endemic areas in the tropics and subtropics. • Immunosuppression of individuals with persistent Strongyloides stercoralis infection can lead to hyperinfection syndrome or disseminated infection, which can be fatal in up to 90% of cases. • First-line therapy for acute and chronic strongyloidiasis is ivermectin, 200 μg/kg orally in a single daily dose for 1 to 2 days. Treatment of hyperinfection syndrome includes reduction of immunosuppression, if possible, and administration of ivermectin (200 μg/kg daily) until larvae are no longer detected in stool for at least 2 weeks.3,17 The spectrum of clinical disease is wide, however, and shorter courses of ivermectin may be sufficient. • Larva currens is a hypersensitivity reaction that refers to the cutaneous manifestation of Strongyloides and should be distinguished from cutaneous larva migrans, which is caused by abortive human infection with an animal hookworm.