Cutaneous Larva Migrans:
"The Creeping Eruption”
“A 28-year-old medical resident and a companion returned from hiking in Central America with pruritic, erythematous, single-track linear and serpiginous lesions located predominantly on their lower extremities. A physician clinically examined the skin disorder and diagnosed the two patients with cutaneous larva migrans after learni! ng that they had been walking barefoot on the beach during their vacation. Both patients were afebrile, and both responded to treatment with oral ivermectin.”
Source: Kitchen, L.W. “Case Studies in International Travelers.” American Family Physician, Aug. 1999. 60(2): 471-474.
Cutaneous larva migrans (CLM) was first described as "the creeping eruption" and diagnosed by a physician in 1874. Today, it is one of the most common helminth (hookworm) infections acquired from subtropical and tropical regions of the world. The CDC defines CLM as a “parasitic skin disease caused by a hookworm larvae that usually infects dogs, cats, and other animals." Humans can acquire the infection by walking barefoot along soil or beaches contaminated with animal feces, which happened in the illustrative case of the two travelers abov! e. The CLM parasite can be found in the southeastern and Gulf states o f the U.S. and in the tropical countries of the Caribbean, South Asia, and Southeast Asia. According to the Dr. Joseph F. Smith Medical Library Foundation, these small, round blood-sucking worms infest about 700 million people worldwide each year.
With increasing globalization and the growing incidence of foreign travel, the parasite continues to show up in many non-endemic countries around the world. CLM is most often a disease of children, utility workers, gardeners, travelers, sunbathers, and others who are exposed to soil or sand contaminated with cat and dog feces.
CLM is caused by various animal hookworm species (e.g. !
Ancylostoma braziliense), and the parasite is acquired from direct skin contact with soil contaminated by dog or cat feces. The normal hosts for these hookworms are cats and dogs, which pass on the roundworm eggs in their feces. The eggs then hatch in the warm, shady, moist, or sandy soil, and they initially feed on the bacteria in the soil before molting twice and developing into their third infective stage. Humans walking barefoot on the beach then become accidentally infected with the larvae, which use their proteases to penetrate through follicles, fissures, or the intact skin of their hosts.
The parasitic infection usually begins with an inflamed papule, often located between the toes, where the hookworm species (e.g. Ancylostom!
a braziliense) larvae enter the skin. Serpentine or linear sin
gle-track lines later mark the course of the larvae as they migrate through the epidermis of the trunk and lower extremities. The larvae can travel very rapidly, sometimes appearing or disappearing at different locations. Symptoms begin to appear within the first two weeks of the patient’s return from a tropical or endemic country, and the erythematous lines can enlarge as much as 1 to 2 cm. per day. However, the larvae cannot complete their life cycle in the human – they encounter a dead-end in these accidental hosts and become trapped in the epidermis layer of the skin.
The lesions caused by cutaneous larva migrans are characteristic of this parasitic infection, and when combined with the patient’s history of possible exposure, the picture is very diagnostic. Sometimes, however, the lesions may be mistaken for fungal infections or inflammatory skin disorders. Pruritis can be quite persistent throughout the i!
nfection, and the patient might experience pain, itchiness, local swelling, and sometimes fever. Vesicles with serous fluid often appear as shown in the picture below. Systemic signs include peripheral eosinophilia and elevated levels of IgE. In very rare cases of CLM, usually in infections with a large number of parasites, pneumonitis (Loeffler syndrome) may occur and myotis may also develop from skin lesions. Sometimes, the larvae even manage to migrate to the small intestine and cause severe eosinophilic enteritis (inflammation).
The condition is usually diagnosed clinically by a physician. Microscopic inspection can be utilized to reveal the hookworm eg!
gs or larvae in the feces or stools. Biopsies, with or without cryo
surgery of the lesions, are not necessary – they do not visualize the migrating parasite and might even result in further development of the local inflammation.
Treatment & Prevention:
If left untreated, the CLM larvae will usually die in the epidermis after several weeks or months, because they are unable to complete their lifecycles in the accidental human hosts. CLM usually responds well to a single dose of oral ivermectin (Strombectol), although the drug is not labeled for this purpose in the U.S. Albendazole (Albenza) and thiabendazole (Mintezol) can also be used to treat the parasite infection. Antibacterial ointments such as Bactroban may be useful in managing secondary infections that result from the pruritis.
CLM can be easily prevented. Skin contact with moist soi! l contaminated with animal feces should be avoided, and adequate footwear should be worn on the beach at all times. Beaches should be kept free of cat and dog feces, and sunbathers should use a towel to provide a barrier when sitting or lying on the ground. Practicing good hygiene is the best way to avoid acquisition of this benign but bothersome parasitic infection.
Douglass, M.C. “Cutaneous Larva Migrans.” eMedicine.com. 24 May 2005. http://www.emedicine.com/derm/topic91.htm
Kitchen, L.W. “Case Studies in International Travelers.” American ! Family Physician, Aug. 1999. 60(2): 471-474.
Meer, Geoff. “Cutaneous Larva Migrans.” Medicine Australia. 18 May 2005. http://www.medicineau.net.au/clinical/medicine/medicine5.html
Padmavathy, L.; Rao, L.L. “Cutaneous Larva Migrans – A Case Report.” Indian Journal of Medical Microbiology, 2005. 23:135-136.
Silverberg, N.B.; Jackson, R.M.; Laude, T.A.; and Tunnessen, W.W. “Picture of the month: Cutaneous larva migrans.” Archives of Pediatric Adolescent Medicine, Feb. 1998. 152(2): 203-204.
Wang, J. “Cutaneous Larva Migrans.” eMedicine.com. 24 May 2005.
Pictures (in order of appearance):
Hookworm Lifecycle Picture from PetStuff Online Newsletter. 27 Aug.1999.
Photomicrograph of! skin showing creeping eruption nematode in burrow X 480 (Kirby-Smith, et. al.)
Department of Pediatrics, University of Wisconsin (Madison)
Department of Dermatology, Washington University School of Medicine
Department of Dermatology, University of Iowa
Archives of Family Medicine
Google Image Search
Amy Olivia Carlson, Program in Human Biology / Stanford University. June 2005.