Cutaneous Larva Migrans

• Hemant K. Satpathy, M.D.

 Basic Information

Description

Cutaneous larva migrans (CLM) is a syndrome defined clinically and parasitologically by subcutaneous larval migration of nematodes. Creeping eruption is the cardinal manifestation. It includes neither diseases in which creeping eruption is due to nonlarval forms of parasites nor diseases without creeping eruptions from subcutaneous migration of larval parasites. Because animal hookworms are the most common cause, some people use the term “hookworm-related cutaneous larva migrans” (HrCLM) instead. Table E1 describes other clinical syndromes associated with unusual helminth infections in humans.

Synonyms

1. CLM

2. Creeping eruption

3. Plumber’s itch

4. Creeping verminous dermatitis

5. Sand worm eruption

6. Duck hunter’s itch

7. Hookworm-related cutaneous larva migrans HrCLM

ICD-10CM CODES
B76.8	Other hookworm diseases
B76.9	Hookworm disease, unspecified

Epidemiology & Demographics

1. •

   Commonly seen in tropical and subtropical countries. In the U.S., it is most prevalent in southeastern states. Florida has the most cases among these states.

2. •

   More often seen in children than adults.

3. •

   Has no racial or sexual predilection.

4. •

   Peak incidence is seen during rainy season.

5. •

   Second to pinworm among helminth infection in developed countries.

6. •

   Most common tropically acquired dermatosis.

7. •

   Most common imported ectoparasites in travelers returning to the U.S. after a holiday.

Risk Factors

Hobbies and occupations that involve contact with warm, moist, sandy soil

1. •

   Tropical or subtropical climate travels

2. •

   Barefoot beach goers or sunbathers

3. •

   Children playing in sandboxes

4. •

   Carpenters, electricians, plumbers, farmers, gardeners, pest exterminators

Etiology

1. •

   Animal hookworms

2. •

   Ancylostoma braziliense (commonest cause)

3. •

   Ancylostoma caninum

4. •

   Uncinaria stenocephala

5. •

   Bunostomum phlebotomum

6. •

   Pelodera strongyloides

7. •

   Gnathostoma species

8. •

   Strongyloides stercoralis

9. •

   Spirulina species

Pathogenesis

The infection is usually acquired via skin contact with the soil or sand contaminated with feces of infected dogs or cats. The filariform larva is the infective form. It penetrates the skin and migrates within the epidermis by releasing protease and hyaluronidase. The inflammatory reaction along the cutaneous tract of their migration results in creeping eruptions. The larvae are believed to lack the collagenase enzymes required to penetrate the basement membrane to invade the dermis. In contrast to cats and dogs, humans are incidental host. Thus, the larvae are unable to complete their natural cycles in humans. The larvae die without treatment and are resorbed within weeks to months of invasion. This explains why CLM is a self-limiting disease and rarely has systemic features.

Clinical Features

1. •

   Often associated with a history of sunbathing, walking barefoot on a beach, or similar activity in a tropical location.

2. •

   Incubation period is around 1 to 6 days.

3. •

   Intense pruritus at the site of invasion within hours of invasion.

4. •

   Many patients report a stinging sensation, which they may misinterpret as a puncture or insect bite.

5. •

   Erythematous papules develop at the larval penetration site. Feet, buttocks, and thighs are most commonly affected anatomical locations.

6. •

   The most frequent and cardinal finding of HrCLM is creeping dermatitis, which takes a few days to develop. It is defined as an erythematous, slightly elevated, linear, or serpiginous track that is 3 mm in width and may be up to 15 to 20 cm in length. The mean number of lesions per person varies from one to three. The creeping track associated with the larva migration may extend a few millimeters to few centimeters daily (Fig. E1). These eruptions last 2 to 8 wk without treatment.

   

7. •

   Edema and vesicobullous lesions along the course of the larva.

8. •

   Rare presentation is hookworm folliculitis. It is characterized by numerous (20-100) follicular, erythematous, and pruritic papules and pustules, located mainly in the buttocks. Generally numerous short tracks are seen arising from these follicular lesions.

9. •

   In case of rare pulmonary involvement, dry cough and wheezing develop 1 week after the dermal invasion.

    

Diagnosis

Diagnosis is made on clinical grounds and history of potential exposure. Clinical characteristics of the creeping trails (length, width, speed of migration, location, duration) help differentiate HrCLM from other causes of creeping dermatitis.

1. •

   Blood tests are not necessary for diagnosis. Theoretically, blood test could detect eosinophilia and elevated IgE level.

2. •

   Biopsy specimens usually show an eosinophilic inflammatory infiltrate but not the migratory parasite. For this reason, biopsy is not indicated to establish the diagnosis. Nonetheless, in case of hookworm folliculitis, skin biopsy specimens may reveal nematode larvae in the follicular canal.

3. •

   Stool studies and serology are not helpful.

4. •

   Radiography of the chest is indicated when migratory pulmonary infiltrates are suspected.

5. •

   A new technology, optical coherence tomography, has been found to identify the larvae in the epidermis, allowing direct removal.

Differential Diagnosis

1. •

   Superficial thrombophlebitis

2. •

   Mondor’s disease

3. •

   Lichen striatus

4. •

   Phytophotodermatitis

5. •

   Herpes zoster

6. •

   Migratory myiasis

7. •

   Scabies

8. •

   Loiasis

9. •

   Dracunculiasis

10. •

    Cercarial dermatitis

11. •

    Onchocerciasis

12. •

    Dirofilariasis

13. •

    Contact dermatitis

14. •

    Creeping hair

15. •

    Jelly fish stings

16. •

    Fascioliasis

17. •

    Bacterial folliculitis

18. •

    Tinea pedis/corporis

19. •

    Impetigo

20. •

    Erythema chronicum migrans of Lyme disease

21. •

    Ground itch

22. •

    Toxocariasis

 

Treatment

1. •

   Oral albendazole and ivermectin are the first-line drug treatments.

2. •

   Oral administration is preferred in the presence of extensive lesions or when topical application fails.

3. •

   Topical application should cover the tracks and area covering up to 2 cm from the leading edge.

4. •

   Albendazole should be given (400 mg orally per day for 3 to 5 days).

5. •

   At times, when oral drugs are contraindicated, topical 10% albendazole creams are applied twice a day for a period of 10 days.

6. •

   Ivermectin should be given (200 mcg/kg given as a single dose).

7. •

   Thiabendazole should be given (25-50 mg/kg divided into twice-daily doses for 2 days).

8. •

   Because of its higher side effect profile when given orally, it is more often applied topically (10%-15% cream or aqueous suspension of 500 mg/5 ml) four times a day for 5 to 10 days.

9. •

   Mebendazole should be given (100 mg orally twice for 3 days).

10. •

    Cryotherapy with liquid nitrogen is obsolete. It is ineffective as the larva is usually located 1 to 2 cm beyond the visible end of the trail, and the larva is capable of withstanding temperature as low as −21° C for more than 5 minutes. Moreover, this procedure is painful and can lead to chronic ulcerations.

11. •

    Specific antihelmintic therapy for pulmonary involvement is generally not required because the illness is usually mild and self-limiting.

12. •

    In the case of hookworm folliculitis, treatment is more difficult than the traditional form and necessitates repeated courses of oral antihelmintic agents.

13. •

    Antihistamines and topical steroids relieve intense pruritus.

14. •

    Antibiotics are indicated for bacterial superinfection.

15. •

    Generally, there should be no attempt to extract the worm.

Complications

1. •

   Secondary bacterial infection

2. •

   Erythema multiforme

3. •

   Migratory eosinophilic pneumonitis (Loeffler syndrome)

4. •

   Eosinophilic enteritis

Prognosis

Self-limiting benign disease. Even without treatment, most cases resolve within 4 to 8 weeks.

Prevention

1. •

   Prohibit pets such as dogs and cats walking on the beaches in tropical areas.

2. •

   Avoid allowing pets in sandboxes.

3. •

   Deworm household pets.

4. •

   Clean up pet droppings.

5. •

   Wear protective footwear while walking on the beach.

6. •

   Avoid tropical beaches frequented by dogs and cats.

7. •

   When lying on tropical beaches potentially frequented by dogs and cats, areas of sand washed by the tide are preferable to dry sand, and mattresses are preferable to towels.

8. •

   Towels and clothes should not touch the ground when hung up for drying.