Cutaneous larva migrans=اليرقة الجلدية المهاجرة |
CUTANEOUS LARVA
MIGRANS
Synonyms.
Creeping eruption, creeping verminous dermatitis, sandworm eruption, plumber's itch, duck hunter's itch. These terms describe a sign (itching and creeping dermatitis) caused by several different parasites
Epidemiology.
Cutaneous larva migrans (CLM) is widely distributed and most commonly found in tropical and sub-tropical areas, especially the southeastern United States, Caribbean, Africa, Central and South America, India, and Southeast Asia. Activities that pose a risk include contact with sand or soil contaminated with animal feces, such as playing in a sandbox, walking barefoot on a beach, and working in crawl spaces under houses.
Etiology and Pathogenesis.
Most often, the larvae of animal hookworms cause hookworm-related CLM (HrCLM). Ancylostoma braziliense is the most common cause. Other skin-penetrating hookworm larvae that produce similar disease include A. caninum, Uncinaria stenocephala (hookworm of European dogs), and Bunostomum phlebotomum (hookworm of cattle). A. caninum causes eosinophilic enteritis as well as cutaneous disease. Cats and dogs are hosts for A. ceylanicum and A. caninum. The human is an aberrant, dead-end host who acquires the parasite from an environment contaminated with animal feces. The infective larvae may remain viable in soil for several weeks. Third-stage larvae penetrate human skin and migrate up to several centimeters a day, usually between the stratum germinativum and stratum corneum. This induces a localized eosinophilic inflammatory reaction. Most larvae are unable to undergo further development or to invade deeper tissues and die after days to months.
Clinical Findings.
The time from exposure to onset of symptoms is usually a few (1 to 6) days. Skin changes are the most prominent findings.
RELATED PHYSICAL FINDINGS.
Systemic signs and symptoms (wheezing, dry cough, urticaria) have been reported in some patients.
CUTANEOUS LESIONS.
The characteristic lesion of HrCLM is an erythematous, raised, and vesicular, linear, or serpentine cutaneous trail 10 and
Another clinical presentation is hookworm folliculitis. The patients usually present with pruritic folliculitis and creeping eruption. The folliculitis consists of 20 to 100 follicular papules and pustules, confined to a particular area of the body, usually the buttocks. Two to 10 serpiginous or linear burrows 1 to 5 cm long may be located in the same or different area. The eruption usually lasts between 2 and 8 weeks, though rarely it has been reported to last up to 2 years.
Laboratory Findings.
There may be a transient peripheral eosinophilia.
Special Tests.
Characteristic creeping eruption, as well as known epidemiologic exposure, are the basis for the diagnosis of HrCLM. The diagnosis of hookworm folliculitis is based on clinical findings alone when pruritic folliculitis is associated with creeping eruption. Otherwise, histologic studies are necessary, and show nematode larvae trapped within the follicular canal, the stratum corneum, or the dermis together with an inflammatory eosinophilic infiltrate. In contrast to creeping dermatitis, skin scrapings in patients with folliculitis may reveal live and dead nematode larvae when examined by light microscopy with mineral oil; nematode larvae may also be seen in the dermis on sections of skin biopsy specimens.
Differential Diagnosis.
There is a confusion between the terms creeping eruption (a sign) and cutaneous larva migrans (CLM, a syndrome), both of which have been used to name a disease, animal HrCLM.
CUTANEOUS LARVA MIGRANS SYNDROME.
CLM should only refer to the infection by animal nematodes in which the infected human is a dead-end host. These nematodes include animal hookworms (HrCLM), Gnathostoma sp. (cutaneous gnathostomiasis), animal filarial nematodes (Spirurina X), Pelodera strongyloides, and various zoonotic species of Strongyloides. By definition, CLM syndrome does not include diseases in which creeping eruption is due to (1) nonlarval forms of parasites (migratory myiasis, dracunculiasis, loiasis, and scabies); (2) larval forms of human nematodes such as S. stercoralis (larva currens); or (3) larval forms of trematodes such as Fasciola gigantica. Clinically, the hallmark of CLM is a creeping eruption but other cutaneous signs related to the subcutaneous migration of nematode's larvae have been described, such as migratory panniculitis and limb swelling.
CREEPING ERUPTION.
The different helminthic diseases causing creeping eruption can be distinguished on the basis of the duration of the disease, the characteristics of the cutaneous trail(s) (number, width and length, and serpiginous or linear nature), the location of the trail and other clinical signs, in addition to classical epidemiologic and laboratory findings . Correct diagnosis is required for appropriate treatment.
Treatment.
First-line treatment for HrCLM is a single dose of ivermectin or a three-day course of albendazole. Cure rates approach 100 percent. Topical therapy with thiabendazole is also an option. The topical application of 10 percent albendazole cream twice a day during 10 days is effective, but it is not available in all countries. There should be no attempt to extract the worm, because it has already migrated beyond the visible lesion by the time it is identified.
Prevention.
Infection with animal hookworms is prevented by avoiding direct skin contact with fecally contaminated soil.
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