Cutaneous Larva Migrans

A SIMPLE GUIDE TO CUTANEOUS LARVA MIGRANS

    by Kenneth Kee   A Family Doctor's Tale

What is Cutaneous Larva migrans?

    Cutaneous Larva migrans is a common skin condition which appears as a red         snake-like itchy rash caused by penetration and subsequent migration of larvae of various worm parasites.

The condition is benign and self-limited.

It is most commonly found in tropical countries.

1.People of all ages are affected but it is more common in children .

2.It is more common in hot tropical climates

3.Certain occupations that involve contact with warm, moist, sandy soil:
Farmer
Gardener

4.Certain hobbies that involve contact with warm, moist, sandy soil:
Tropical climate travel
Barefoot beachgoers
Children building sandcastles

The larvae usually hatch from eggs laid in animal faeces and then penetrate through the intact skin of the children or adults.

After shedding their covering, they begin migrating in the epidermis.

Because they are unable to penetrate through the dermis, the disease remains limited to the skin of humans.

THE MOST COMMON PARASITES ARE:
DOG HOOKWORMS:
Ancylostoma braziliense
Ancylostoma caninum
Uncinaria stenocephala

Rarer causes are:
Bunostomum phlebotomum (cattle hookworm)
Ancylostoma ceylonicum
Ancylostoma tubaeforme (cat hookworm)
Necator americanus (human hookworm)
Ancylostoma duodenale

Symptoms:

1.prickling sensation at the site within 30 minutes of larva penetration of the skin
2.Intense itchiness
3.Red linear lesions that moves
4.history of sunbathing,
5.walking barefoot on the beach in a tropical location

Signs:

1.Itchy, red, raised papules or vesicles
2.snakelike, slightly elevated, red tunnels that are 2-3mm wide and 3-4 cm long from the penetration site
3.Vesicles with clear fluid
4.Secondary infection
5.Tract movement of 1-2 cm/day
6.peripheral eosinophilia (Loeffler syndrome),
7.migratory lung infiltrates,
8.Lesions are typically present on the distal lower extremities,
the dorsa of the feet and the interdigital spaces of the toes,
anogenital region,
the buttocks,
the hands, and
the knees.

Diagnosis is mostly based on the
1.classic clinical appearance of the eruption.

2.peripheral eosinophilia on a Complete Blood Count

3.increased IgE levels on total serum immunoglobulin determinations.

4. skin biopsy taken just before leading edge of a tract may show
a larva (periodic acid-Schiff positive) in a
suprabasalar burrow,
basal layer tracts,
spongiosis
intraepidermal vesicles,
necrotic keratinocytes,
an epidermal and upper dermal chronic inflammatory infiltrate with many eosinophils.

Complications:
1. secondary bacterial infection, usually with Streptococcus pyogenes, may lead to cellulitis.

2. Allergic reactions may occur.

Treatment:

The condition is usually self-limiting.
The intense itchiness and risk for infection may require treatment.

Invasive treatment:

1.liquid nitrogen cryotherapy for progressive end of larval burrow.

2.electrocautery

Medication:

1.Thiabendazole
Thiabendazole is the best medication
Topical application is used for early, localized lesions.
The oral route is preferred for widespread lesions or unsuccessful topical treatment.

2.Mebendazole (Vermox)
Broad-spectrum anthelmintic that inhibits microtubule assembly and irreversibly blocks glucose uptake, thereby depleting the parasites' glycogen stores.

Other effective treatments include
3.albendazole,
4.ivermectin.

In most cases there is decreased itchiness within 24-48 hours and lesions resolve in 1 week.

5.Antibiotics are given if there are secondary bacterial superinfections.

6.Antihistamines are given for severe itchiness

   Prognosis:

The prognosis is excellent.

This is a self-limiting disease.

Humans are accidental hosts and the larva usually dies within 4-8 weeks.

The lesions usually will disappear within 8 weeks to 1 year depending on complications.

Travellers to tropical regions and pet owners should be made aware of this condition.

Prevention is by avoiding direct skin contact with possible fecally contaminated soil.