The cause of larva currens -

There may be a dermatitis, with erythema and itching at the site of penetration of the filariform larvae, paicularly when large numbers of larvae enter the skin. In those sensitised by prior infection, there may be an allergic response. This may prevent circulation in the blood of the larvae, which may instead migrate in skin, leading to a form of creeping eruption or larva migrans. The term larva currens (meaning 'racing larva') has been applied to this rapidly progressing linear uicarial tracks caused by migrating strongyloides larvae. These often follow autoinfection and sta perianally. REF:TEXTBOOK OF MEDICAL PARASITOLOGY;CKJ PANIKER;6TH EDITION;PAGE NO 173