Background
Cutaneous larva migrans (CLM) is the most common tropically acquired dermatosis whose earliest description dates back more than 100 years. Cutaneous larva migrans manifests as an erythematous, serpiginous, pruritic, cutaneous eruption caused by accidental percutaneous penetration and subsequent migration of larvae of various nematode parasites. Cutaneous larva migrans is most commonly found in tropical and subtropical geographic areas and the southwestern United States. It has become an endemic in the Caribbean, Central America, South America, Southeast Asia, and Africa. However, the ease and the increasing incidence of foreign travel by the world's population have no longer confined cutaneous larva migrans to these areas. [1, 2, 3, 4, 5, 6, 7]
Also see the Medscape Drugs & Diseases article Pediatric Cutaneous Larva Migrans.
Pathophysiology
In cutaneous larva migrans (CLM), the life cycle of the parasites begins when eggs are passed from animal feces into warm, moist, sandy soil, where the larvae hatch. They initially feed on soil bacteria and molt twice before the infective third stage. By using their proteases, larvae penetrate through follicles, fissures, or intact skin of the new host. After penetrating the stratum corneum, the larvae shed their natural cuticle. Usually, they begin migration within a few days.
In their natural animal hosts, the larvae of cutaneous larva migrans are able to penetrate into the dermis and are transported via the lymphatic and venous systems to the lungs. They break through into the alveoli and migrate to the trachea, where they are swallowed. In the intestine they mature sexually, and the cycle begins again as their eggs are excreted.
Humans are accidental hosts, and the larvae lack the collagenase needed to penetrate the basement membrane and invade the dermis. Therefore, cutaneous larva migrans remains limited to the skin when humans are infected.
The pruritic symptoms occur secondary to an immune response to both the larvae and their products. [8]
Etiology
Common etiologies and where the parasites of cutaneous larva migrans (CLM) are most commonly found include the following:
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Ancylostoma caninum (dog hookworm) is found in Australia.
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Uncinaria stenocephala (dog hookworm) is found in Europe.
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Bunostomum phlebotomum (cattle hookworm)
Rare etiologies include the following:
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Ancylostoma ceylonicum
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Ancylostoma tubaeforme (cat hookworm)
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Necator americanus (human hookworm)
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Strongyloides papillosus (parasite of sheep, goats, and cattle)
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Strongyloides westeri (parasite of horses)
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Ancylostoma duodenale
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Pelodera (Rhabditis) strongyloides [11]
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Gnathostorna spinigerum
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Strongyloides stercoralis
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Bunostornum phlebotomum
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Strongyloides myopotami
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Strongyloides procyonis [8]
Epidemiology
Frequency
Cutaneous larva migrans is rated second to pinworm among helminth infections in developed countries. Prevalence is high in regions of warm climate, where individuals may be more inclined to walk barefoot (eg, beaches, lower socioeconomic communities) and come in contact with animal feces. [12, 13]
Race
No specific racial predilection exists because cutaneous larva migrans depends on exposure.
Sex
Cutaneous larva migrans demonstrates no specific sexual predilection because cutaneous larva migrans depends on exposure.
Age
Cutaneous larva migrans can affect persons of all ages because it depends on exposure, but it tends to be seen in children more commonly than in adults.
Prognosis
The prognosis for cutaneous larva migrans is excellent. Cutaneous larva migrans is a self-limiting disease. Humans are accidental, dead-end hosts, with the larva dying and the lesions resolving within 4-8 weeks, as long as 1 year in rare cases.
Patient Education
Persons who travel to tropical regions and pet owners should be aware of this condition. For patient education resources, see the patient education article Foreign Travel.
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A patient who was sunbathing nude on a beach in Martinique presented with classic erythematous, serpiginous tracts on the left heel.
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Cutaneous larva migrans on the right thumb.
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Cutaneous larva migrans on the left thigh.
