Answer

Diagnostic Challenge

CJEM 2002;4(1):63

The Answer is A: Cutaneous larva migrans. Cutaneous larva migrans is the most frequent serpiginous lesion seen in travellers, especially those returning from the Caribbean. With increasing ease of international travel, patients with this infection may present to emergency departments in nontropical countries.

Cutaneous larva migrans is an animal hookworm infestation usually caused by the Ancylostoma genus of nematodes. It is confined predominantly to tropical and subtropical countries, although its distribution is ubiquitous. Eggs of the nematode (usually A. braziliense) are found most commonly in dog and cat feces. Unsuspecting travellers are exposed to the larvae by sitting or walking on a beach that has been contaminated with dog or cat feces. The larvae penetrate into human skin and advance at a rate of approximately 3 cm per day.

It is characterized clinically by an almost pathognomonic "creeping eruption," which is intensely itchy. These sinuous inflammatory trails may be easily visible on the surface of the skin, usually the soles of the feet or on the buttocks.

Treatment with topical thiabendazole is usually successful within 10 days of commencement.¹ More extensive lesions can be treated with a single oral dose of ivermectin or 3 to 7 days of albendazole.²

Larva currens and gnathostomiasis are also considered linear, migratory infestations caused by parasites. The former produces an urticarial wheel that moves at a rate of 5 to 10 cm/h and lasts for only a few hours at a time.² It tends to recur over the course of a few days. Gnathostomiasis is a rare infection that is caused by an animal nematode acquired when humans consume inadequately cooked fish, shellfish or amphibians. Infection can present anywhere from 1 month to years after exposure, often with both visceral and cutaneous manifestations. The migratory, serpiginous, cutaneous track of gnathostomiasis is much longer, wider and more edematous than that of the dog and cat hookworm. The worm can also migrate throughout the body and cause a variety of presentations, including ocular, central nervous system and pulmonary disease.²

References

1. Jelinek T, Maiwald H, Nothdurft HD, Loscher T. Cutaneous larva migrans in travelers: synopsis of histories, symptoms, and treatment of 98 patients. Clin Infect Dis 1994;19:1062-6.
2. Kain, KC. Skin lesions in returned travellers. Med Clin North Am 1999;83:4.

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