Larva currens, also called cutaneous strongyloidiasis, is an itchy skin condition that is triggered by infection from a parasitic worm called Strongyloides stercoralis. For this reason, larva currens is sometimes referred to as strongyloidiasis. The term larva currens, however, is more specific and ultimately a more accurate description of the condition, as the parasite infects during its larval stage. The disease was first identified in 1926.
The condition is called larva currens because it pinpoints the variant of the worm when it causes the ailment — at its immature, or larval, stage of development. It is also characterized by migration of the larvae, burrowing deep into the tissue and creating thread-like, linear lesions. Also called cutaneous strongyloidiasis, larva currens is classified as a cutaneous condition, meaning that it involves infection of the skin.
Episodes of larva currens occur for a number of hours, with no symptoms for weeks or months at a time. In some cases, it appears not long after the Strongyloides stercoralis causes the infection. In others, it might manifest itself much later, years after the infection has occurred.
Larva currens is the result of an autoinfection, which means that infection is caused by direct contact with the larvae. A common cause is walking barefoot on soil bearing the infectious worms. This kind of infection ensures that episodes reappear over the course of several years. People with weakened or defective immune systems can die from the condition if it develops into a hyperinfection syndrome.
The standard treatment for larva currens is anthelmintic therapy, which involves drugs that get rid of parasitic worms. Examples of anthelmintic drugs include ivermectin, albendazole, and thiabendazole. Cyclosporine, or cyclosporine A, a drug used to suppress the immune system after organ transplantation, has also been used due to its anthelmintic properties. In cases of bacterial infection, antibiotics might be applied as well. The goal of treatment for larva currens is to end the infection and avoid complications.
Follow-up on larva currens involves examining the stool of the patient in two- to three-month intervals to make sure the worms are completely gone or to monitor therapeutic response. This serial sampling is performed about four to eight months after completion of anthelmintic therapy. Low occurrence of the parasites or total eradication is typically achieved between six and 18 months after the conclusion of treatment. If the worms persist, however, additional treatment may be needed.
