Larva currens: the usefulness of the agar plate method

Creeping eruption caused by Strongyloides stercoralis is called larva currens, while those caused by other parasites are called larva migrans. To detect the parasite, the direct smear method was used. However, this method is not very sensitive in detecting S. stercoralis. A 62-year-old male with polyarteritis nodosa cutanea had an erythematous creeping eruption in various regions, such as his lumbar region, abdomen and thigh. The diagnosis of larva currens was made by the clinical appearance and the detection of S. stercoralis in his feces using the direct smear method and the agar plate method. This is the first reported case of larva currens in Japan. The agar plate method was useful and more sensitive than the usual direct smear method for detecting the S. stercoralis in feces and for elucidating the effects of treatment with antiparasitic drugs.