Late relapse of cutaneous larva migrans

Abstract

Cutaneous larva migrans is a common disease in the tropics and among travelers. The itchy, serpentigious rash often appears within days to weeks after transmission. There are only few reported cases of late relapses. Here, we present a case of a relapse of cutaneous larva migrans more than one year after exposure.

Introduction

Cutaneous larva migrans (CLM) is common in the tropics and is caused by non-human hookworms, primarily Ancylostoma caninum and A. braziliense. The larva enters the skin upon direct contact with contaminated soil. Normally, the rash, which is serpentigious, migrating and pruritic, develops within the first week after transmission. Only few cases of late appearances and relapses have been reported previously, and none with a relapse more than one year after exposure.

Case

A 22-year-old man was seen in May 2021 due to a late relapse of CLM. Between August to December 2019, he was attending a high school on Zanzibar. The school has previously experienced outbreaks of CLM [1].

In January 2020, he presented with several serpiginous rashes on the right foot. He received an unknown medication from a fellow student and the rash disappeared. In May 2020, he developed two new itchy elements on the left foot. He was diagnosed with CLM at Aarhus University Hospital, Denmark. Treatment with a single dose of ivermectin 18 mg was effective.

In May 2021, 16 months after the primary rash, a new, itchy, migrating rash developed under his left foot (Fig. 1). Examination for immune deficiency was normal, except from a slightly decreased IgG2. Treatment with albendazole 400 mg for three days was effective.

Fig. 1.

Cutaneous larva migrans under the left foot.

Discussion

There have been few reported cases of CLM relapses. A French child presented with two rashes at different locations more than two months apart after traveling to Guadeloupe island [2]. A British man presented with a migrating rash five months after returning from Tanzania [3]. A man from Ghana had a relapse two months after he was diagnosed with CLM [4], and a Danish man visiting Zanzibar developed new rashes four and six months after his primary CLM [1].

In this case, reinfection was excluded as the patient had not been traveling outside of Denmark since 2019. Another explanation might be a late presentation of CLM. The larvae may lie dormant for months increasing the incubation period [5], but the rash has not previously been described to occur as long as 16 months after exposure. Lastly, one can discuss whether the ivermectin treatment only put the larvae in a dormant stage, making it possible for them to start migrating again at a later stage. Oral Ivermectin treatment is generally described with high efficacy but there has been reported a few cases with treatment failures [1].

Funding

None.

Ethical approval

N/A.

Consent

Written informed consent was obtained from the patient for publication of this case report and accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal on request.

CRediT authorship contribution statement

Fredrikke Dam Larsen: Methodology, Investigation, Resources, Writing – original draft, Visualization. Carsten Schade Larsen: Conceptualization, Methodology, Writing – review & editing, Supervision. Sanne Jespersen: Conceptualization, Methodology, Resources, Writing – review & editing, Supervision. FDL: Acquisition of data, analysis/interpretation, writing (drafting). CSL: Study design, writing (revising). SJ: Study design, acquisition of data, writing (revising).

Declarations of interest

None.