Summary about Disease
Cutaneous larva migrans (CLM), also known as creeping eruption, is a skin infection caused by hookworm larvae that typically infest dogs and cats. Humans contract it when larvae penetrate the skin, usually on the feet, buttocks, or back, after contact with contaminated sand or soil. The larvae migrate within the epidermis (outer layer of skin), creating itchy, raised, winding tracks. The condition is self-limiting, meaning it eventually resolves on its own, but treatment can relieve symptoms and shorten the duration.
Symptoms
Intensely itchy, red, raised, and winding tracks or lines on the skin.
Tracks are typically 2-3 mm wide and can grow several millimeters per day.
Blisters or small bumps (papules) may form along the tracks.
Most commonly affects the feet, buttocks, back, or other areas that come into contact with contaminated soil or sand.
Itching is often worse at night.
Causes
CLM is caused by the larvae of hookworms that commonly infect dogs and cats. The most common species responsible are Ancylostoma braziliense and *Ancylostoma caninum*. These animals deposit hookworm eggs in their feces. In warm, moist sandy soil, the eggs hatch and develop into infective larvae. Humans become infected when their skin comes into direct contact with this contaminated soil or sand. The larvae penetrate the skin but cannot complete their life cycle in humans. Therefore, they migrate within the epidermis, causing the characteristic tracks.
Medicine Used
Oral antihelminthic medications: Ivermectin (single dose) or albendazole (taken for 1-3 days) are the most common and effective treatments.
Topical antihelminthic medications: Thiabendazole cream is sometimes used, but oral medications are generally preferred due to their higher efficacy.
Is Communicable
No, cutaneous larva migrans is not communicable from person to person. It is contracted through direct contact with contaminated soil or sand containing hookworm larvae.
Precautions
Avoid walking barefoot or sitting/lying directly on sand or soil in areas where animals may defecate, particularly beaches and sandboxes.
Wear shoes and protective clothing when gardening or working in soil.
Use beach mats or towels when sitting or lying on the beach.
Regularly deworm pets (dogs and cats) to prevent hookworm infections.
Practice good hygiene, including washing hands thoroughly after contact with soil or sand.
Avoid areas known to be contaminated.
How long does an outbreak last?
Without treatment, CLM will eventually resolve on its own as the larvae die. This can take weeks to months (typically 2-8 weeks). Treatment with antihelminthic medication significantly shortens the duration, often resolving the infection within a few days.
How is it diagnosed?
Diagnosis is typically made based on the characteristic clinical presentation: the appearance of the itchy, raised, winding tracks on the skin, and the history of potential exposure to contaminated soil or sand. A skin biopsy is generally not required but may be considered in atypical cases to rule out other conditions.
Timeline of Symptoms
Initial penetration: Within minutes to hours of exposure, a tingling or prickling sensation may be felt as the larvae penetrate the skin.
Early phase (1-7 days): A small, red bump or papule may appear at the site of entry.
Migratory phase (days to weeks): The characteristic itchy, raised, winding tracks begin to appear, extending several millimeters each day. The itching becomes more intense.
Resolution (weeks to months, if untreated): The larvae eventually die, and the tracks gradually fade. Itching subsides. Secondary bacterial infection due to scratching can prolong the symptoms.
Important Considerations
Secondary bacterial infection can occur from scratching, so keeping the area clean and avoiding scratching is important. If signs of infection (increased redness, swelling, pus) develop, seek medical attention.
Although generally a benign condition, the intense itching can be very bothersome and disrupt sleep.
People traveling to tropical and subtropical regions should be particularly aware of the risk and take appropriate precautions.
Individuals with weakened immune systems may experience more severe or prolonged symptoms.
Recurrence is possible if re-exposure to contaminated soil or sand occurs.