Approach

Diagnosis is based on a typical clinical presentation together with suggestive history. Further investigation is not usually necessary.

Clinical presentation

Travel history is essential in determining risk of exposure to infection. CLM represents one of the most common parasitic infestations in returning travellers.[4]​​[29] Most patients in the US have recently returned from a holiday at a beach destination in the tropics or subtropics, especially the Caribbean, Brazil, Mexico, and Southeast Asia.[4]​​[11] History of walking barefoot and/or sunbathing on a beach in an endemic area will provide further diagnostic clues. Based on studies of returned travellers, the incubation period for CLM is usually a few days to a few weeks, although, in rare cases, onset of lesions has been reported 1 month or longer after return from travel.[2][11][30]​​​​

The characteristic sign of CLM is an erythematous, serpiginous, or linear raised track about 3 mm wide.[Figure caption and citation for the preceding image starts]: Typical appearance of cutaneous larva migransFrom the collection of Dr Gregory L. Zalar; used with permission [Citation ends].com.bmj.content.model.Caption@4ef741c5 This may extend from a few millimetres to a few centimetres daily.[31] Associated pruritus is a key clinical finding and may be intense and uncomfortable, even preventing sleep.[2]

Vesiculobullous or papular lesions have been found to occur along the larval tracks in 10% to 40% of cases; some reports have noted bullae several centimetres in diameter.[3][32] Rarely, a returning traveller may present with folliculitis due to creeping larvae becoming trapped in the sebaceous follicular canal. In such cases, pruritic papules and pustules are found in association with relatively short tracks, primarily on the buttocks.[5][33]

Larval tracks may be single or multiple and are located most commonly on the feet, thighs, and buttocks, related to the most common areas to come into contact with contaminated soil.[4]​​[11] However, lesions can occur on any unprotected part of the body, including hands, arms, trunk, scalp, face, breasts, and genitals.[34]

Investigations

Diagnosis is based on clinical grounds, and further investigation is rarely necessary.[2]​ A minority of patients may demonstrate eosinophilia on full blood count and/or elevated total IgE levels; however, these findings are non-specific and these tests are therefore not recommended.[11][22]​​​[35]​ Skin biopsy or scrapings rarely identify migrating larvae because the larvae are usually located a few centimetres ahead of the creeping eruption, and skin biopsy should be performed only in cases of associated folliculitis.[5][11]​ No approved serological or molecular diagnostic methods are available. Epiluminescence microscopy is still an emerging technique. It is non-invasive and the larvae may be visualised migrating in the skin, although sensitivity seems to be low.[36]

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