Larva Currens

Q: What is Larva currens?

Answer: Larva currens is also called "running" larva of strongyloidiasis. It was first described almost seven decades ago. The most common entry site is via skin due to contaminated soil. Person-to-person transmission occurs due to fecal contamination, larvae-bearing fomites, and sexual contact. Donor-derived strongyloidiasis has been described in transplant recipients. Another major issue with transplant patients is the reactivation of remote infection in the form of hyperinfection/disseminated disease, also called accelerated autoinfection.

Larva currens is a dermatologic manifestation as raised, pink, pruritic, evanescent streaks along the lower trunk, thighs, and buttocks, resulting from migrating larvae through the subcutaneous tissues. It can be dramatic. As the larva moves, the progress can be approximately 1 cm in 5 minutes and 5 to 15 cm per hour. Larvae leave behind a thin red line that gradually fades to brown and disappears within 48 hours. It can be associated with urticaria, pruritus, angioedema, or rash.

Ivermectin is the treatment.

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References:

1. ARTHUR RP, SHELLEY WB. Larva currens; a distinctive variant of cutaneous larva migrans due to Strongyloides stercoralis. AMA Arch Derm 1958; 78:186.

2. Zubrinich CM, Puy RM, O'Hehir RE, Hew M. Strongyloides infection as a reversible cause of chronic urticaria. J Asthma Allergy 2019; 12:67.

3. Tian Y, Monsel G, Paris L, Danis M, Caumes E. Larva Currens: Report of Seven Cases and Literature Review. Am J Trop Med Hyg. 2022 Dec 19;108(2):340-345. doi: 10.4269/ajtmh.21-0135. PMID: 36535252; PMCID: PMC9896332.

4. Puerta-Peña M, Calleja Algarra A. Larva Currens in Strongyloides Hyperinfection Syndrome. N Engl J Med. 2022 Apr 21;386(16):1559. doi: 10.1056/NEJMicm2115708. PMID: 35443110.