Cutaneous Larva Migrans in Traveler: Chile Case Report

Cutaneous larva migrans (CLM), the most common tropical dermatitis, is typically associated with travel to endemic areas. However, a recent case report highlights the possibility of acquiring this infection even without international travel. The case, documented in a study published in December 2015, details a three-year-old boy in Chile who developed CLM despite having no history of travel outside the country.

Understanding Cutaneous Larva Migrans

CLM is caused by nematodes – parasitic worms – that are typically hosted by cats and dogs. Humans become accidental hosts when infectious larvae penetrate the skin. The infection manifests clinically as a slow-growing, elevated, linear, erythematous (reddened), and pruritic (itchy) plaque, most commonly found on the soles of the feet. Diagnosis is primarily clinical, based on the characteristic appearance of the lesion and a history of potential exposure, traditionally linked to travel in regions where the parasite is prevalent.

An Unusual Case: Autochthonous CLM in Chile

The case report details a three-year-old boy presenting with a linear lesion on his foot consistent with CLM. Importantly, the patient had no history of travel outside of Chile. Investigators found that the child had contact with dogs, suggesting a local source of infection. He was treated with a single dose of ivermectin, a medication commonly used to treat parasitic infections, and experienced complete resolution of the lesion.

This case is significant because it represents the first reported instance of CLM acquired within Chile by a child. Traditionally, CLM has been categorized as a “traveler’s dermatitis,” meaning it’s contracted during visits to tropical or subtropical regions. The finding challenges this conventional understanding and suggests that CLM can occur in non-endemic areas where dogs and cats carry the parasite.

How Does Transmission Occur?

The larvae of these nematodes are typically excreted in the feces of infected animals. When these feces contaminate soil or sand, the larvae can survive and actively penetrate human skin upon contact. Common scenarios for infection include walking barefoot on contaminated surfaces, or children playing in sandboxes or soil where animal feces are present. The larvae then migrate under the skin, leaving behind the characteristic winding track that defines the condition.

Diagnosis and Treatment

Diagnosis of CLM is usually made clinically, based on the appearance of the skin lesion and the patient’s history. While laboratory tests can confirm the presence of the parasite, they are not always necessary. Treatment typically involves topical or oral anti-parasitic medications, such as ivermectin. As demonstrated in the Chilean case, a single dose of ivermectin can be effective in resolving the infection.

Implications for Public Health

The report of autochthonous CLM in Chile raises important questions about the prevalence of the parasite in domestic animals and the potential for local transmission. It highlights the need for increased awareness among healthcare professionals and the public, even in areas not traditionally considered endemic for CLM. Veterinary care and responsible pet waste disposal are crucial in preventing the spread of the parasite.

Further research is needed to determine the extent of CLM transmission in Chile and other non-endemic regions. Understanding the prevalence of the parasite in animal populations and identifying risk factors for human infection are essential steps in developing effective prevention strategies. The case also underscores the importance of considering CLM in the differential diagnosis of skin lesions, even in patients without a history of travel.

Ultrasound Findings

Recent research, as indicated by findings from Wiley Online Library, explores the use of very high- and high-frequency ultrasound to aid in the diagnosis of CLM. While details are limited without access to the full study, this suggests that ultrasound imaging may offer a non-invasive method for visualizing the larval tracks under the skin, potentially improving diagnostic accuracy.

While CLM is generally a self-limiting condition, prompt diagnosis and treatment can alleviate symptoms and prevent secondary infections. The case from Chile serves as a reminder that this parasitic infection can occur in unexpected places, and vigilance is key to protecting public health.