Carpenters Pest exterminators. Most larva migrans seen in New Zealand arises during overseas holidays, but it has rarely been reported in those who have never been out of the country. How does hookworm infection occur? Parasite eggs are passed in the faeces of infested animals to warm, moist, sandy soil, where the larvae hatch. On contact with human skin, the larvae can penetrate through hair follicles, cracks or even intact skin to infect the human host.
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Search Menu Abstract Cutaneous larva migrans caused by the larvae of animal hookworms is the most frequent skin disease among travelers returning from tropical countries. Complications impetigo and allergic reactions , together with the intense pruritus and the significant duration of the disease, make treatment mandatory. Freezing the leading edge of the skin track rarely works. Cutaneous larva migrans is the most frequent skin disease among travelers returning from tropical countries [ 1 ].
It is now easy to treat with new oral antihelmintic agents, which are both well tolerated and effective. Cutaneous larva migrans is caused by the larvae of animal hookworms, of which Ancylostoma braziliense is the species most frequently found in humans [ 2 , 3 ]. These hookworms generally live in the intestines of domestic pets such as dogs and cats and shed their eggs via feces to soil usually sandy areas of beaches or under houses.
Humans are infected in tropical and subtropical areas of endemicity by contact with contaminated soil. The hookworm larva burrows through intact skin but remains confined to the upper dermis, since humans are incidental hosts.
Larval migration through the skin is marked by an intensely pruritic, linear, or serpiginous track figure 1 , left known as a creeping eruption. Note that creeping eruptions occur in many other human skin diseases.
Hookworm folliculitis is an uncommon form of cutaneous larva migrans, marked by pustular folliculitis of the buttocks figure 1 , right [ 4 ]. Figure 1 Left, A cutaneous serpiginous track characteristic of cutaneous larva migrans. Right, Hookworm folliculitis, an uncommon clinical form of cutaneous larva migrans. Figure 1 Open in new tab Download slide Left, A cutaneous serpiginous track characteristic of cutaneous larva migrans.
Cutaneous larva migrans usually heals spontaneously within weeks or months. Complications include impetigo and local or general allergic reactions. These potential complications, together with the intense pruritus and the duration of the disease, make treatment mandatory. However, optimal management is controversial: in 1 study, 22 German patients with cutaneous larva migrans had received 12 different treatments, including surgery and French brandy, before they were referred to a specialized center [ 7 ].
The most effective treatment is topical or oral administration of antihelmintic agents, such as albendazole, thiabendazole, and ivermectin.
Topical Treatments Freezing. Freezing the leading edge of the skin track with ethylene chloride spray, solid carbon dioxide, or liquid nitrogen rarely works, as the larva is usually located several centimeters beyond the visible end of the trail. In 1 series, cryotherapy repeated applications of liquid nitrogen was unsuccessful for 6 patients and resulted in severe blistering or ulceration in 2 patients [ 7 ].
In another series, none of 7 patients treated with liquid nitrogen was cured [ 6 ]. Because this method is both ineffective and painful, it should be avoided. The thiabendazole cream was prepared by crushing mg tablets of thiabendazole in a water-soluble base. In most patients the pruritus ceased and larval track migration halted within 48 h of treatment. In the other 2 cases, treatment was successful after 2 weeks in 1 case and after 4 weeks in the other [ 7 ].
The main advantage of topical treatments is the absence of systemic side effects. Their main disadvantages are that they have limited value for multiple lesions and hookworm folliculitis and that they require multiple daily applications for several days. Oral Treatments Thiabendazole. Thiabendazole is the drug with which there has been the most experience in the oral treatment of cutaneous larva migrans [ 5 , 9—12 ] table 1. Thiabendazole is poorly effective when given as a single dose.
Thiabendazole is less well tolerated than either albendazole or ivermectin. In a study of patients treated with thiabendazole 1. Albendazole is a third-generation heterocyclic antihelmintic drug. It has been used for about a decade to treat intestinal helminthiases, such as ascaridiasis, enterobiasis, ancylostomiasis, trichuriasis, and strongyloidiasis.
Trials of albendazole in the treatment of cutaneous larva migrans have yielded conflicting results with respect to the optimal dosage. Albendazole has also been used with success at higher daily doses mg for 3 consecutive days. However, in the largest trial of albendazole in cutaneous larva migrans involving 26 Italian tourists , treatment with mg for 5 consecutive days failed for 2 patients [ 18 ].
In addition, in a study of 11 French tourists, a single mg dose failed in 6 cases [ 19 ]. In 2 of the 3 studies involving tourists, albendazole failed for 2 of 26 Italian patients [ 18 ] and 6 of 11 French patients [ 19 ], while the duration of follow-up was not given in the third study [ 14 ]. Albendazole was well tolerated in trials involving patients with cutaneous larva migrans.
Other publications suggest that albendazole is well tolerated unless given at high dosages or for extended periods, such as those required for hydatid disease [ 21 ]. Ivermectin, an avermectin B derivative, is active against Onchocerca volvulus and other nematodes, including gastrointestinal helminths. Its mechanism of action is poorly understood [ 22 ]. Since then, the efficacy of ivermectin has been confirmed in 3 larger studies.
Table 3 Treatment of cutaneous larva migrans with a single oral mg dose of ivermectin. Table 3 Open in new tab Download slide Treatment of cutaneous larva migrans with a single oral mg dose of ivermectin.
Another study involved 67 Belgian tourists treated with a single dose 12 mg of ivermectin. The median intervals until disappearance of the pruritus and lesions were 3 days range, 1—7 days for the patients who received a second dose, and 9 days range, 4—30 days for those who received a third dose.
Only 2 patients were not cured by ivermectin [ 27 ]. Ivermectin has been well tolerated in studies of patients with cutaneous larva migrans, and no adverse effects have been reported in indications other than filariasis [ 28 ]. An open study [ 19 ] compared the efficacy of single doses of oral ivermectin 12 mg and oral albendazole mg in the treatment of cutaneous larva migrans.
No major adverse effects were observed. The investigators concluded that a single mg dose of ivermectin was more effective than a single mg dose of albendazole for the treatment of cutaneous larva migrans [ 19 ]. Prevention Because tourists are usually infected by walking or lying on tropical sandy beaches contaminated by dog feces, the best way to prevent cutaneous larva migrans is to ban dogs from beaches figure 2 , top [ 29 ]. Because this is clearly impossible in developing tropical countries, where dogs are ubiquitous, it is best to wear shoes when walking in sandy areas.
When on tropical beaches frequented by dogs, it is best to lie on sand washed by the tide or to use a mattress; avoid lying on dry sand, even on a towel figure 2 , bottom. Table 2 Treatment of cutaneous larva migrans with oral alben-dazole.
Bicho geográfico (larva migrans cutânea)
Cutaneous larva migrans
Larva migrans cutanea
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