 |
| Fig. 33.2 Larva currens. Biopsy demonstrates migrating larva of
Strongyloides stercoralis in the dermis. (Courtesy of the Fitzsimons
Army Medical Center teaching files.) |
Larva currens, or “racing larva,” is caused by
Strongyloides stercoralis, a nematode with a normal
life cycle similar to the hookworm.
Strongyloides,
however, is unique in that it can complete its life
cycle within the human host and bypass the obligate
soil phase of the hookworms. Autoinfection may
occur to a point of overwhelming infestation and
host death, especially in immunocompromised
victims. The serpentine eruption of larva currens
appears much the same as creeping eruption but is
more likely to occur on the thighs, buttocks, or
perineum due to larval penetration from the nearby
colon. The eruption is more fleeting and lasts no
more than a few days, during which the larva’s
migratory speed through the dermis may be clocked
at up to 10 cm/hr (Fig. 33-2). A nonspecific rash or
hives may also occur because of hypersensitivity to
the parasite.
